Sperm Cell Quotes

It is a well-documented fact that guys will not ask for directions. This is a biological thing. This is why it takes several million sperm cells... to locate a female egg, despite the fact that the egg is, relative to them, the size of Wisconsin.

Okay, forget about the disrespect, facts don’t care about your feelings. It, turns out that every chromosome, every cell in Caitlyn Jenner’s body, is male, with the exception of some of his sperm cells. … It turns out that he still has all of his male appendages. How he feels on the inside is irrelevant to the question of his biological self.

that each ejaculation contains several billion sperm cells –or roughly the same number as there are people in the world– which means that, in himself, each man holds the potential of an entire world. And what would happen, could it happen, is the full range of possibilities: a spawn of idiots and geniuses, of the beautiful and the deformed, of saints, catatonics, thieves, stock brokers, and high-wire artists. Each man, therefore, is the entire world, bearing within his genes a memory of all mankind. Or, as Leibniz put it: “Every living substance is a perpetual living mirror of the universe.

JAY: No really. Be secure. Pretend I'm a sperm cell. Here. I take the string out of the... hood of my sweatshirt, affix it to my behind for a tail, like so... LENORE: What in God's name are you doing? JAY: Pretend, Lenore. Be an ovum. Be strong. Let me hypothetically batter at you. Batter batter. Surrender to the unreal of the real interior. LENORE: Are you supposed to be a sperm, wriggling your sweatshirt-string like that? JAY: I can feel the strength of your membrane, Lenore.

It means that your birth, with all your particulars, is a wildly improbable event, and hence precious. You won the sweepstakes by being born at all. Think of all the wallflower sperm and egg cells. You made it, buddy. Whew! What a staggering wonder! What a thing to rejoice in! The lottery wasn't fixed! God didn't rig it! You won fair and square! What a miracle!

[...] Deep within, her female organs began to contract and release. She felt the path of his seed and now in her mind she could see a golden trail. How was this even possible? Dear God, how was any of this even possible? Now she could see the chrysalis of her genetic material, a bright burning light at the end of a tunnel. The imagery made her smile then laugh. She could see his sperm, like lightning [...] If his DNA wanted to make a child, why wouldn't it move at an accelerated rate? She felt the moment when her egg received his sperm and their child began all the fantastic portentous crazy cell replications. [...]

Similarly deadly to small wriggling cells, if a bit more quackish, is vanadium, element twenty-three, which also has a curious side effect in males: vanadium is the best spermicide ever devised. Most spermicides dissolve the fatty membrane that surrounds sperm cells, spilling their guts all over. Unfortunately, all cells have fatty membranes, so spermicides often irritate the lining of the vagina and make women susceptible to yeast infections. Not fun. Vanadium eschews any messy dissolving and simply cracks the crankshaft on the sperm’s tails. The tails then snap off, leaving

The idea that female choice (conscious or not) can happen after or during intercourse rather than as part of an elaborate precopulatory courtship ritual turns the standard narrative inside out and upside down. If the female’s reproductive system has evolved intricate mechanisms for filtering and rejecting the sperm cells of some men while helping along those of a man who meets criteria of which she may be utterly unaware, Darwin’s “coy female” starts looking like what she is: an anachronistic male fantasy.

You began in a sperm cell as a strand of DNA that still doesn't know who you are.

So many women come to me saying, “I have lost too, and this one, and this one”. So many embryos retreat to flesh: the live cell of the mother. Don’t tell me that it will happen for me, when the only sure thing is a miracle: the sperm nuzzling in its nest and the egg that opens, explodes.

The truth is that life itself is brutally, obscenely unfair. Consider all those other millions of sperm cells that were just as good as the one that resulted in you, and where are they now? Dead, nowhere.

The number of sperm cells released in a single ejaculation of one man is 175 thousand times more than the number of eggs a woman produces in her entire lifetime. It can be more than the number of people in North America; hundreds of millions.

Men are even worse: a hundred rounds of cell division are needed to make sperm, with each round linked inexorably to more mutations. Because sperm production goes on throughout life, round after round of cell division, the older the man, the worse it gets. As the geneticist James Crow put it, the greatest mutational health hazard in the population is fertile old men.

Sperm is the storehouse of male sexual energy. A single ejaculation has 200 to 500 million sperm cells, each a potential human being. There are enough spermotozoa lost in a single orgasm to populate the entire United States if each cell was to fertilize an egg.

she knows what he means, that they don’t have to touch. the same thing that’s happening to him is happening to her. she doesn’t need to crawl under the table ans suck his dick. too tire to interest either one of them. the flow is strong between them. the emotional tone. let it express itself. he sees her in her wallow and feel his pelvic muscles begin to quiver. he say, tell me to stop and i’ll stop. but he doesn’t wait for her to reply. there isn’t time. the tails of his sperm cells are lashing already. she is his sweetheart and lover and slut undying. he doesn’t have to do the unspeakable thing he wants to do. he only has to speak it. because they’re beyond every model of established behavior. he only wants to say the words.” _Eric Packer

Units of hereditary information, encoded in DNA and packaged on chromosomes, are transmitted through sperm and egg into an embryo, and from the embryo to every living cell in an organism’s body.

Consider the genesis of a single-celled embryo produced by the fertilization of an egg by a sperm. The genetic material of this embryo comes from two sources: paternal genes (from sperm) and maternal genes (from eggs). But the cellular material of the embryo comes exclusively from the egg; the sperm is no more than a glorified delivery vehicle for male DNA—a genome equipped with a hyperactive tail. Aside from proteins, ribosomes, nutrients, and membranes, the egg also supplies the embryo with specialized structures called mitochondria. These mitochondria are the energy-producing factories of the cell; they are so anatomically discrete and so specialized in their function that cell biologists call them “organelles”—i.e., mini-organs resident within cells. Mitochondria, recall, carry a small, independent genome that resides within the mitochondrion itself—not in the cell’s nucleus, where the twenty-three pairs of chromosomes (and the 21,000-odd human genes) can be found. The exclusively female origin of all the mitochondria in an embryo has an important consequence. All humans—male or female—must have inherited their mitochondria from their mothers, who inherited their mitochondria from their mothers, and so forth, in an unbroken line of female ancestry stretching indefinitely into the past. (A woman also carries the mitochondrial genomes of all her future descendants in her cells; ironically, if there is such a thing as a “homunculus,” then it is exclusively female in origin—technically, a “femunculus”?) Now imagine an ancient tribe of two hundred women, each of whom bears one child. If the child happens to be a daughter, the woman dutifully passes her mitochondria to the next generation, and, through her daughter’s daughter, to a third generation. But if she has only a son and no daughter, the woman’s mitochondrial lineage wanders into a genetic blind alley and becomes extinct (since sperm do not pass their mitochondria to the embryo, sons cannot pass their mitochondrial genomes to their children). Over the course of the tribe’s evolution, tens of thousands of such mitochondrial lineages will land on lineal dead ends by chance, and be snuffed out. And here is the crux: if the founding population of a species is small enough, and if enough time has passed, the number of surviving maternal lineages will keep shrinking, and shrinking further, until only a few are left. If half of the two hundred women in our tribe have sons, and only sons, then one hundred mitochondrial lineages will dash against the glass pane of male-only heredity and vanish in the next generation. Another half will dead-end into male children in the second generation, and so forth. By the end of several generations, all the descendants of the tribe, male or female, might track their mitochondrial ancestry to just a few women. For modern humans, that number has reached one: each of us can trace our mitochondrial lineage to a single human female who existed in Africa about two hundred thousand years ago. She is the common mother of our species. We do not know what she looked like, although her closest modern-day relatives are women of the San tribe from Botswana or Namibia. I find the idea of such a founding mother endlessly mesmerizing. In human genetics, she is known by a beautiful name—Mitochondrial Eve.

To the ancients, bears symbolized resurrection. The creature goes to sleep for a long time, its heartbeat decreases to almost nothing. The male often impregnates the female right before hibernation, but miraculously, egg and sperm do not unite right away. They float separately in her uterine broth until much later. Near the end of hibernation, the egg and sperm unite and cell division begins, so that the cubs will be born in the spring when the mother is awakening, just in time to care for and teach her new offspring. Not only by reason of awakening from hibernation as though from death, but much more so because the she-bear awakens with new young, this creature is a profound metaphor for our lives, for return and increase coming from something that seemed deadened. The bear is associated with many huntress Goddesses: Artemis and Diana in Greece and Rome, and Muerte and Hecoteptl, mud women deities in the Latina cultures. These Goddesses bestowed upon women the power of tracking, knowing, 'digging out' the psychic aspects of all things. To the Japanese the bear is the symbol of loyalty, wisdom, and strength. In northern Japan where the Ainu tribe lives, the bear is one who can talk to God directly and bring messages back for humans. The cresent moon bear is considered a sacred being, one who was given the white mark on his throat by the Buddhist Goddess Kwan-Yin, whose emblem is the crescent moon. Kwan-Yin is the Goddess of Deep Compassion and the bear is her emissary. "In the psyche, the bear can be understood as the ability to regulate one's life, especially one's feeling life. Bearish power is the ability to move in cycles, be fully alert, or quiet down into a hibernative sleep that renews one's energy for the next cycle. The bear image teaches that it is possible to maintain a kind of pressure gauge for one's emotional life, and most especially that one can be fierce and generous at the same time. One can be reticent and valuable. One can protect one's territory, make one's boundaries clear, shake the sky if need be, yet be available, accessible, engendering all the same.

They also come in a sumptuously wide range of sizes—nowhere more strikingly than at the moment of conception, when a single beating sperm confronts an egg eighty-five thousand times bigger than it (which rather puts the notion of male conquest into perspective). On average, however, a human cell is about twenty microns wide—that is about two hundredths of a millimeter—which is too small to be seen but roomy enough to hold thousands of complicated structures like mitochondria, and millions

Doc was collecting marine animals in the Great Tide Pool on the tip of the Peninsula. It is a fabulous place: when the tide is in, a wave-churned basin, creamy with foam, whipped by the combers that roll in from the whistling buoy on the reef. But when the tide goes out the little water world becomes quiet and lovely. The sea is very clear and the bottom becomes fantastic with hurrying, fighting, feeding, breeding animals. Crabs rush from frond to frond of the waving algae. Starfish squat over mussels and limpets, attach their million little suckers and then slowly lift with incredible power until the prey is broken from the rock. And then the starfish stomach comes out and envelops its food. Orange and speckled and fluted nudibranchs slide gracefully over the rocks, their skirts waving like the dresses of Spanish dancers. And black eels poke their heads out of crevices and wait for prey. The snapping shrimps with their trigger claws pop loudly. The lovely, colored world is glassed over. Hermit crabs like frantic children scamper on the bottom sand. And now one, finding an empty snail shell he likes better than his own, creeps out, exposing his soft body to the enemy for a moment, and then pops into the new shell. A wave breaks over the barrier, and churns the glassy water for a moment and mixes bubbles into the pool, and then it clears and is tranquil and lovely and murderous again. Here a crab tears a leg from his brother. The anemones expand like soft and brilliant flowers, inviting any tired and perplexed animal to lie for a moment in their arms, and when some small crab or little tide-pool Johnnie accepts the green and purple invitation, the petals whip in, the stinging cells shoot tiny narcotic needles into the prey and it grows weak and perhaps sleepy while the searing caustic digestive acids melt its body down. Then the creeping murderer, the octopus, steals out, slowly, softly, moving like a gray mist, pretending now to be a bit of weed, now a rock, now a lump of decaying meat while its evil goat eyes watch coldly. It oozes and flows toward a feeding crab, and as it comes close its yellow eyes burn and its body turns rosy with the pulsing color of anticipation and rage. Then suddenly it runs lightly on the tips of its arms, as ferociously as a charging cat. It leaps savagely on the crab, there is a puff of black fluid, and the struggling mass is obscured in the sepia cloud while the octopus murders the crab. On the exposed rocks out of water, the barnacles bubble behind their closed doors and the limpets dry out. And down to the rocks come the black flies to eat anything they can find. The sharp smell of iodine from the algae, and the lime smell of calcareous bodies and the smell of powerful protean, smell of sperm and ova fill the air. On the exposed rocks the starfish emit semen and eggs from between their rays. The smells of life and richness, of death and digestion, of decay and birth, burden the air. And salt spray blows in from the barrier where the ocean waits for its rising-tide strength to permit it back into the Great Tide Pool again. And on the reef the whistling buoy bellows like a sad and patient bull.

First of all, your very existence is so miraculous you should feel seen and celebrated! First, the odds of you being born are one in a million because your mom carries over one million eggs during her lifetime. Crazy, but that’s not even close to the mathematical phenomenon you are. Based on recent research, scientists have figured out that the egg that formed you was choosy and could determine which of your father’s 250 million sperm cells it wanted to connect with. If the egg that created you chose any other sperm, your sibling would be holding this book because you never would have been born.

Our prototypical behavior has occurred. How was it influenced by events when the egg and sperm that formed that person joined, creating their genome—the chromosomes, the sequences of DNA—destined to be duplicated in every cell in that future person’s body? What role did those genes play in causing that behavior?

More importantly still, stem cell-derived gametes would allow multiple generations of selection to be compressed into less than a human maturation period, by enabling iterated embryo selection. This is a procedure that would consist of the following steps:48 1 Genotype and select a number of embryos that are higher in desired genetic characteristics. 2 Extract stem cells from those embryos and convert them to sperm and ova, maturing within six months or less.49 3 Cross the new sperm and ova to produce embryos. 4 Repeat until large genetic changes have been accumulated. In this manner, it would be possible to accomplish ten or more generations of selection in just a few years. (The procedure would be time-consuming and expensive; however, in principle, it would need to be done only once rather than repeated for each birth. The cell lines established at the end of the procedure could be used to generate very large numbers of enhanced embryos.)

You seek to trap me into an inconsistency. If you were an amoeba who could consider individuality only in connection with single cells and if you were to ask a sperm whale, made up of thirty quadrillion cells, whether it was one or many, how could the sperm whale answer in a way that would be comprehensible to the amoeba?

Well, start with a cell again. Inside the cell is a nucleus, and inside each nucleus are the chromosomes—forty-six little bundles of complexity, of which twenty-three come from your mother and twenty-three from your father. With a very few exceptions, every cell in your body—99.999 percent of them, say—carries the same complement of chromosomes. (The exceptions are red blood cells, some immune system cells, and egg and sperm cells, which for various organizational reasons don’t carry the full genetic package.) Chromosomes constitute the complete set of instructions necessary to make and maintain you and are made of long strands of the little wonder chemical called deoxyribonucleic acid or DNA—“the most extraordinary

(William) Hamilton recast the central ideas (of the evolutionary theory of aging) in mathematical form. Though this work tells us a good deal about why human lives take the course they do, Hamilton was a biologist whose great love was insects and their relatives, especially insects which make both our lives and an octopus’s life seem rather humdrum. Hamilton found mites in which the females hang suspended in the air with their swollen bodies packed with newly hatched young, and the males in the brood search out and copulate with their sisters there inside the mother. He found tiny beetles in which the males produce “and manhandle sperm cells longer than their whole bodies. Hamilton died in 2000, after catching malaria on a trip to Africa to investigate the origins of HIV. About a decade before his death, he wrote about how he would like his own burial to go. He wanted his body carried to the forests of Brazil and laid out to be eaten from the inside by an enormous winged Coprophanaeus beetle using his body to nurture its young, who would emerge from him and fly off. 'No worm for me nor sordid fly, I will buzz in the dusk like a huge bumble bee. I will be many, buzz even as a swarm of motorbikes, be borne, body by flying body out into the Brazilian wilderness beneath the stars, lofted under those beautiful and un-fused elytra [wing covers] which we will all hold over our “backs. So finally I too will shine like a violet ground beetle under a stone.

Do you consider yourself athletic? How would you rate yourself, say, as a swimmer? Average, below average, maybe a little above average? So-so? Terrible? Well, I’ve got news for you: whether you know it or not, you are a world-class super-Olympic gold medal swimmer. I’m not kidding. You know how I know that? Because I took anatomy, physiology, bacteriology, and chemistry in college, as part of my science minor. And here’s what I learned: we all start out the same way, as tiny sperm cells. In order for you to be born, assuming your daddy had an average sperm count, you had to have out-swum some 200,000 other sperm. And it was uphill all the way. Now, I do not know what motivated you, but that little tail was wiggling like mad, and you were screaming, “Out of my way! Out of my way! I want to teach school! I want to dance! I want to be in real estate! I want to be a journalist!” or whatever it was you were screaming at the top of your little sperm voice.

For reasons we don't yet understand, the tendency to synchronize is one of the most pervasive drives in the universe, extending from atoms to animals, from people to planets. Female friends or coworkers who spend a great deal of time together often find that their menstrual periods tend to start around the same day. Sperm swimming side by side en route to the egg beat their tails in unison, in a primordial display of synchronized swimming. Sometimes sync can be pernicious: Epilepsy is caused by millions of brain cells discharging in pathological lockstep, causing the rhythmic convulsions associated with seizures. Even lifeless things can synchronize. The astounding coherence of a laser beam comes from trillions of atoms pulsing in concert, all emitting photons of the same phase and frequency. Over the course of millennia, the incessant effects of the tides have locked the moon's spin to its orbit. It now turns on its axis at precisely the same rate as it circles the earth, which is why we always see the man in the moon and never its dark side.

When your grandmother was five months pregnant with your mother, the precursor cell of the egg you developed from was already present in your mother’s ovaries. This means that before your mother was even born, your mother, your grandmother, and the earliest traces of you were all in the same body—three generations sharing the same biological environment.1 This isn’t a new idea: embryology textbooks have told us as much for more than a century. Your inception can be similarly traced in your paternal line. The precursor cells of the sperm you developed from were present in your father when he was a fetus in his mother’s womb.

However, there is one fundamental feature of the sexes which can be used to label males as males, and females as females, throughout animals and plants. This is that the sex cells or ‘gametes’ of males are much smaller and more numerous than the gametes of females. This is true whether we are dealing with animals or plants. One group of individuals has large sex cells, and it is convenient to use the word female for them. The other group, which it is convenient to call male, has small sex cells. The difference is especially pronounced in reptiles and in birds, where a single egg cell is big enough and nutritious enough to feed a developing baby for several weeks. Even in humans, where the egg is microscopic, it is still many times larger than the sperm. As we shall see, it is possible to interpret all the other differences between the sexes as stemming from this one basic difference.

Women are anatomically different in one other very significant way: they are the sacred keepers of human mitochondria—the vital little powerhouses of our cells. Sperm pass on none of their mitochondria during conception, so all mitochondrial information is transferred from generation to generation through mothers alone. Such a system means that there will be many extinctions along the way. A woman endows all her children with her mitochondria, but only her daughters have the mechanism to pass it onward to future generations. So if a woman has only sons or no children at all—and that happens quite often, of course—her personal mitochondrial line will die with her. All her descendants will still have mitochondria, but it will come from other mothers on other genetic lines. In consequence, the human mitochondrial pool shrinks a little with every generation because of these localized extinctions.

Familial schizophrenia (like normal human features such as intelligence and temperament) is thus highly heritable but only moderately inheritable. In other words, genes-hereditary determinants-are crucially important to the future development of the disorder. If you possess a particular combination of genes, the chance of developing the illness is extremely high: hence the striking concordance among identical twins. On the other hand, the inheritance of the disorder across generations is complex. Since genes are mixed and matched in every generation, the chance that you will inherit that exact permutation of variants from your father or mother is dramatically lower. In some families, perhaps, there are fewer gene variants, but with more potent effects-thereby explaining the recurrence of the disorder across generations. In other families, the genes may have weaker effects and require deeper modifiers and triggers-thereby explaining the infrequent inheritance. In yet other families, a single, highly penetrant gene is accidentally mutated in sperm or egg cells before conception, leading to the observed cases of sporadic schizophrenia.

A few hundred million years later, some of these eukaryotes developed a novel adaptation: they stayed together after cell division to form multicellular organisms in which every cell had exactly the same genes. These are the three-boat septuplets in my example. Once again, competition is suppressed (because each cell can only reproduce if the organism reproduces, via its sperm or egg cells). A group of cells becomes an individual, able to divide labor among the cells (which specialize into limbs and organs). A powerful new kind of vehicle appears, and in a short span of time the world is covered with plants, animals, and fungi.37 It’s another major transition. Major transitions are rare. The biologists John Maynard Smith and Eörs Szathmáry count just eight clear examples over the last 4 billion years (the last of which is human societies).38 But these transitions are among the most important events in biological history, and they are examples of multilevel selection at work. It’s the same story over and over again: Whenever a way is found to suppress free riding so that individual units can cooperate, work as a team, and divide labor, selection at the lower level becomes less important, selection at the higher level becomes more powerful, and that higher-level selection favors the most cohesive superorganisms.39 (A superorganism is an organism made out of smaller organisms.) As these superorganisms proliferate, they begin to compete with each other, and to evolve for greater success in that competition. This competition among superorganisms is one form of group selection.40 There is variation among the groups, and the fittest groups pass on their traits to future generations of groups. Major transitions may be rare, but when they happen, the Earth often changes.41 Just look at what happened more than 100 million years ago when some wasps developed the trick of dividing labor between a queen (who lays all the eggs) and several kinds of workers who maintain the nest and bring back food to share. This trick was discovered by the early hymenoptera (members of the order that includes wasps, which gave rise to bees and ants) and it was discovered independently several dozen other times (by the ancestors of termites, naked mole rats, and some species of shrimp, aphids, beetles, and spiders).42 In each case, the free rider problem was surmounted and selfish genes began to craft relatively selfless group members who together constituted a supremely selfish group.

The key point is that these patterns, while mostly stable, are not permanent: certain environmental experiences can add or subtract methyls and acetyls, changing those patterns. In effect this etches a memory of what the organism was doing or experiencing into its cells—a crucial first step for any Lamarck-like inheritance. Unfortunately, bad experiences can be etched into cells as easily as good experiences. Intense emotional pain can sometimes flood the mammal brain with neurochemicals that tack methyl groups where they shouldn’t be. Mice that are (however contradictory this sounds) bullied by other mice when they’re pups often have these funny methyl patterns in their brains. As do baby mice (both foster and biological) raised by neglectful mothers, mothers who refuse to lick and cuddle and nurse. These neglected mice fall apart in stressful situations as adults, and their meltdowns can’t be the result of poor genes, since biological and foster children end up equally histrionic. Instead the aberrant methyl patterns were imprinted early on, and as neurons kept dividing and the brain kept growing, these patterns perpetuated themselves. The events of September 11, 2001, might have scarred the brains of unborn humans in similar ways. Some pregnant women in Manhattan developed post-traumatic stress disorder, which can epigenetically activate and deactivate at least a dozen genes, including brain genes. These women, especially the ones affected during the third trimester, ended up having children who felt more anxiety and acute distress than other children when confronted with strange stimuli. Notice that these DNA changes aren’t genetic, because the A-C-G-T string remains the same throughout. But epigenetic changes are de facto mutations; genes might as well not function. And just like mutations, epigenetic changes live on in cells and their descendants. Indeed, each of us accumulates more and more unique epigenetic changes as we age. This explains why the personalities and even physiognomies of identical twins, despite identical DNA, grow more distinct each year. It also means that that detective-story trope of one twin committing a murder and both getting away with it—because DNA tests can’t tell them apart—might not hold up forever. Their epigenomes could condemn them. Of course, all this evidence proves only that body cells can record environmental cues and pass them on to other body cells, a limited form of inheritance. Normally when sperm and egg unite, embryos erase this epigenetic information—allowing you to become you, unencumbered by what your parents did. But other evidence suggests that some epigenetic changes, through mistakes or subterfuge, sometimes get smuggled along to new generations of pups, cubs, chicks, or children—close enough to bona fide Lamarckism to make Cuvier and Darwin grind their molars.

How Aging Stems from Trade-Offs Aging occurs because our body must make a trade-off between reproducing and staying in good repair, according to the author’s “disposable soma” theory. Given a limited supply of energy, the amount that goes to making and protecting sperm and eggs tips the scale away from ensuring that “somatic” cells—skin, bone, muscle, and so on—remain in good condition. As a result, cells accumulate damage over time, which ultimately causes some organ or another to become diseased. If bodily functioning is sufficiently compromised, death ensues.

In gorillas’ winner-take-all approach to mating, males compete to see who gets all the booty, as it were. So, although an adult silverback gorilla weighs in at around four hundred pounds, his penis is just over an inch long, at full mast, and his testicles are the size of kidney beans, though you’d have trouble finding them, as they’re safely tucked up inside his body. A one-hundred-pound bonobo has a penis three times as long as the gorilla’s and testicles the size of chicken eggs. The extra-large, AAA type (see chart in Chapter Fifteen). In bonobos, since everybody gets some sugar, the competition takes place on the level of the sperm cell, not at the level of the individual male.

Fr. Benedict Groeschel says it in his uniquely northern New Jersey way: “Celibacy means that we belong exclusively to the Lord, from our brain cells to our sperm cells.

Metabolically active cells, such as those of the liver, kidneys, muscles, and brain, have hundreds or thousands of mitochondria, making up some 40 per cent of the cytoplasm. The egg cell, or oocyte, is exceptional: it passes on around 100000 mitochondria to the next generation. In contrast, blood cells and skin cells have very few, or none at all; sperm usually have fewer than 100. All in all, there are said to be 10 million billion mitochondria in an adult human, which together constitute about 10 per cent of our body weight.

Meiosis is an elegant process but in any organism errors in meiosis sometimes occur. These errors may be the result of mistakes in separation of the chromosomes during division or of an incorrect exchange of genetic information during chiasma formation. Many genetic disorders in humans can be traced back to errors in the formation of the gametes in meiosis. Mistakes in meiosis can result in an abnormal number of chromosomes in an egg or sperm cell. If this egg or sperm is then involved in fertilization, the zygote will exhibit an abnormal number of chromosomes. The child produced from this zygote (following mitosis and differentiation) will have cells with too few or too many chromosomes

My daughter’s eggs are silver points of potential energy, the light at the beginning of the tunnel, a near-life experience. Boys don’t make sperm—their proud “seed”—until they reach puberty. But my daughter’s sex cells, our seed, are already settled upon prenatally, the chromosomes sorted, the potsherds of her parents’ histories packed into their little phospholipid baggies.

By now it’s got as much in common with its origins as a humpback whale would have with the sperm cells from a therapsid lizard. Still,

The creation of a human being from the union of a sperm and an egg. Think about it. A single fertilized egg cell gives rise to many trillions of cells. Impressive enough already. But how do these trillions of cells know how to organize themselves into a human body? Into a human brain? How do they know where to be?” Alyssa smiled stupidly.

Reprogramming is what John Gurdon demonstrated in his ground-breaking work when he transferred the nuclei from adult toads into toad eggs. It’s what happened when Keith Campbell and Ian Wilmut cloned Dolly the Sheep by putting the nucleus from a mammary gland cell into an egg. It’s what Yamanaka achieved when he treated somatic cells with four key genes, all of which code for proteins highly expressed naturally during this reprogramming phase. The egg is a wonderful thing, honed through hundreds of millions of years of evolution to be extraordinarily effective at generating vast quantities of epigenetic change, across billions of base-pairs. None of the artificial means of reprogramming cells comes close to the natural process in terms of speed or efficiency. But the egg probably doesn’t quite do everything unaided. At the very least, the pattern of epigenetic modifications in sperm is one that allows the male pronucleus to be reprogrammed relatively easily. The sperm epigenome is primed to be reprogrammed6. Unfortunately, these priming chromatin modifications (and many other features of the sperm nucleus), are missing if an adult nucleus is reprogrammed by transferring it into a fertilised egg. That’s also true when an adult nucleus is reprogrammed by treating it with the four Yamanaka factors to create iPS cells. In both these circumstances, it’s a real challenge to completely reset the epigenome of the adult nucleus. It’s just too big a task. This is probably why so many cloned animals have abnormalities and shortened lifespans. The defects that are seen in these cloned animals are another demonstration that if early epigenetic modifications go wrong, they may stay wrong for life. The abnormal epigenetic modification patterns result in permanently inappropriate gene expression, and long-term ill-health.

All this reprogramming of the genome in normal early development changes the epigenome of the gametes and creates the new epigenome of the zygote. This ensures that the gene expression patterns of eggs and sperm are replaced by the gene expression patterns of the zygote and the subsequent developmental stages. But this reprogramming also has another effect. Cells can accumulate inappropriate or abnormal epigenetic modifications at various genes. These disrupt normal gene expression and can even contribute to disease, as we shall see later in this book. The reprogramming of the egg and the sperm prevent them from passing on from parent to offspring any inappropriate epigenetic modifications they have accumulated. Not so much wiping the slate clean, more like re-installing the operating system.

Here’s the sequence of epigenetic events in very early development: The male and female pronuclei (from the sperm and the egg respectively) are carrying epigenetic modifications; The epigenetic modifications get taken off (in the immediate post-fertilisation zygote); New epigenetic modifications get put on (as the cells begin to specialise). This is a bit of a simplification. It’s certainly true that researchers can detect huge swathes of DNA demethylation during stage 2 from this list. However, it’s actually more complicated than this, particularly in respect of histone modifications. Whilst some histone modifications are being removed, others are becoming established. At the same time as the repressive DNA methylation is removed, certain histone marks which repress gene expression are also erased. Other histone modifications which increase gene expression may take their place. It’s therefore too naïve to refer to the epigenetic changes as just being about putting on or taking off epigenetic modifications. In reality, the epigenome is being reprogrammed.

In 2012, Japanese cell biologists Katsuhiko Hayashi and Mitinori Saitou announced they had used the Yamanaka factors to reprogram adult mouse skin cells in a dish into iPS cells. They then added more chemicals to turn these stem cells into egg and sperm progenitor cells, the precursors of eggs and sperm. After they placed the same artificial cells into mouse ovaries, the cells matured into eggs. When they put induced sperm precursor into mouse testes, these cells matured into sperm. These induced eggs and sperm were used for mouse IVF, resulting in perfectly healthy baby mice.

They were simply the moanings of sperm cells locked away too long in scrotums.

I read once that a woman can carry around DNA from the men who’ve ejaculated inside her for the rest of her life. They cut open a bunch of dead women’s brains and found male DNA, which at first they thought was from pregnancy, but later they realized it was in too many women, not just ones with sons. The sperm, they reasoned, are basically moving DNA, and they don’t just burrow into available eggs but any cells they can find. I didn’t want to house his genetic code. What did it do inside you? Why was he making me carry it?

Cancer: the code breaks down, becomes disorganized, lets cells proliferate indiscriminately. A disease of information. AIDS: the immune system (the secret defences of the body) is suppressed. Obsessive fear of contiguity, of flows (sperm, blood, saliva), of contact. A disease of communication. What if all this reflected a brute, instinctive refusal of the flows of communic ation, of sperm, of sex, of words? If there were in all this an 'instinctive', vital resistance to the extension of flows and circuits - at the cost of a new mortal pathology, AIDS and cancer, which would ultimately be protecting us from something even more serious, or would at least be serving as an alarm signal? After all, neurosis is what man invents to protect him from madness.

It was a random chance meeting of one particular sperm from a crowd and one particular egg from whichever ones popped out of the party room to look for adventure. It was hope that things would develop to the point where there was a real human being in there, and not just a collection of cells, and some more hope that the whole thing would coalesce and cook until done, and pop out pissed off and viable and ready to keep growing.

Another insect, a scale insect, has an even more bizarre genetic parasite. When its eggs are fertilized, sometimes more than one sperm penetrates the egg. If this happens, one of the sperm fuses with the egg’s nucleus in the normal way; the spare sperm hang around and begin dividing as the egg divides. When the creature matures, the parasitic sperm cells eat out its gonads and replace them with themselves. So the insect produces sperm or eggs that are barely related to itself, an astonishing piece of genetic cuckoldry.

Biological inheritance speaks to the idea that the germ cells (sperm and eggs) are affected by significant environmental events, and that these changes in the genome are then passed on to descendants. Epigenetics offers us the knowledge and the means by which we can enhance physical and mental health, both in our offspring and ourselves.

that unique protein. That binding destroys all Y sperm cells but leaves X sperm cells intact.” As Sue’s jaw dropped, Foster said, “The Pentagon has elevated this danger to its highest threat level. Thanks

Ironically, in the Middle Ages, before the discovery of the human sperm and eggs, the Catholic Church taught that the soul entered the human foetus at the time of quickening, when the mother can first feel the foetus move inside her. But this is about 18–24 weeks of gestation, well after the time at which most abortions are performed, and even longer since the foetus was a preimplantation embryo, so this teaching has been quietly forgotten.

Rêves sexuels : je suis à Lille, devenue repaire de délinquants, casseurs, etc. Chicago, en vérité. Avec des filles très jeunes, je cours, franchis des dunes, des terrains vagues, me couchant sur le sol pour échapper aux bandes, invisibles en fait. On arrive dans une maison, sous un porche. Il y a un garçon, qui déshabille une poupée, assez grande, il s'approche de la fille qui m'accompagnait, assez insignifiante. Il la pénètre et jouit aussitôt, comme dans un gros plan de film X. Je vois le sperme couler sur la vulve. Je suis étonnée que cette fille « sage » se soit ainsi laissé surprendre (c'est le terme qui me vient alors), sans manifester de honte ou de chagrin. Qui est-elle ? Le moi ancien, celle que je n'ai pas été, que je voudrais avoir été et qui ne s'est réalisée que tardivement ?

Mothers not only pass the harms of endocrine-disrupting chemicals on to their fetuses but on to even more distant generations. When a mother is exposed to EDCs, so too are her fetus's germ cells, which develop into eggs or sperm. "It's thought that during that exposure, the chemical can target those germ cells and do what we call reprogramming, or making epigenetic changes," says Flaws. "That can be a permanent change that gets carried through generations, because those germ cells will eventually be used to make the next generation, and those fetuses will have abnormal germ cells that would then go on to make the next generation." In the mid-20th century, scientists documented this in women who took a synthetic form of estrogen, called diethylstilbestrol or DES, to prevent miscarriages.? The drug worked as intended, and the women gave birth to healthy babies. But once some of those children hit puberty, the girls developed vaginal and breast cancer. The boys developed testicular cancer, and some suffered abnormal development of the penis. Scientists called them DES daughters and sons. "When those DES daughters and sons had children, we now have DES granddaughters and grandsons, and a lot of them have increased risk of those same cancers and reproductive problems," says Flaws. "Even though it was their great-grandmother that took DES and they don't have any DES in their system-their germ cells have been reprogramming, and they're passing down some of these disease traits." And now toxicologists are gathering evidence that mothers are passing microplastics and nanoplastics complete with EDCs and other toxic substances- to their fetuses. In 2021, scientists announced that they'd found microplastics in human placentas for the first time, both on the fetal side and maternal side.Later that year, another team of researchers found the same, and they also tested meconium-a newborn's first feces and discovered microplastic there too. Children are consuming microplastics, then, before they're even born.

The precursor cells of the sperm you developed from were present in your father when he was a fetus in his mother’s womb.2

A tree starts out as we do, as the union of two haploid gametes, the egg and the sperm. Cells divide again and again to become embryos. An infinitesimally small number of embryos become seedlings, and out of these, a tiny subset become trees. Time may stand still for decades in some seeds that enter dormancy until conditions for growth become suitable. Time may stop for decades as the seedling exists in the shade, garnering just enough energy for survival but not enough for growth. Time speeds up as sunlight is reached and the tree explodes in sudden growth and then proceeds along its trajectory to reproduction, senescence, and death. In some trees, like the gray birch and balsam fir, maximum life span is usually shorter than our own. In many others it is close to ours, while in a few trees, including the bristlecone pines, a life span of four thousand years is not impossible. Bristlecone pines grow extremely slowly because they live in a cold climate (the White Mountains of California) and because they have little water and few nutrients. They nevertheless stay a step or two ahead of decay and death because the climate also dries their deadwood. It takes them thousands of years to experience the growth, and life, that a white pine in Maine experiences in two hundred summers. Trees must be growing to be alive, but different species grow, and therefore live, at very different rates. Thus, even to a tree, both time and life are relative.

10 Common Reasons for IVF Failure  In-vitro fertilization or IVF provides a means towards parenthood to couples struggling with natural pregnancy. Although IVF is a successful, safe, and effective technique some couples may struggle with multiple IVF failures. According to Dr Vandana Narula, MBBS, MD (Obstetrics & Gynaecology), a lot of factors contribute to the success or failure of IVF. The best infertility specialist in sector 43 Chandigarh advises you to not lose hope and discuss the opportunities with your doctor. 10 Common Reasons for IVF Failure The infertility & IVF specialist in Mohali gives the following common reasons for IVF failure: 1. Poor Sperm Quality The quality of sperm determines the quality of the embryo. Men with certain medical conditions including azoospermia or diabetes may procedure poor quality and quantity of sperm. This can either hamper the development of the embryo or lead to an abnormal embryo. 2. Low Anti-Mullerian Hormone (AMH) Values AMH is a hormone secreted by cells in the egg. A good level of AMH in the woman’s blood indicates good ovarian reserve. Women with low AMH values may procedure unhealthy eggs that may not be implanted. 3. Implantation Failure Implantation failure is one of the common causes of IVF failures. It is usually caused by: A non-receptive uterus lining, thin lining, or lining affected by genital tuberculosis. Prevailing immunological conditions make the uterine environment hostile for the embryos. The endometrium has an inbuilt mechanism to reject poor-quality embryos. 4. Poor Quality of Eggs and Embryos The quality of eggs plays a significant role in IVF failure. The quality of eggs is directly related to the age of a woman and her health. The human egg consists of 23 chromosomes. If any of these chromosomes are missing or arranged incorrectly, they can produce abnormal embryos. A woman’s age also plays a key role in the egg quality. With advancing age, the eggs become less healthy and are prone to genetic abnormalities. This can make it difficult for them to be fertilized by sperm and lead to abnormal embryos.

Nicolaas Hartsoeker published drawings that showed miniature mini-humans in sperm, replete with head, hands, and feet all tucked origami-like into the sperm’s head,

Imagine you were composing a symphony, and you’d written it down by hand onto sheet music, of which you have only one copy. If you wanted to experiment with the theme, you’d be crazy to write over the only copy you have, and risk messing it up with something that doesn’t work. You’d photocopy it, and use that one to play around, while making sure the original was preserved intact as a back-up. That’s not a bad way to think about genome duplications. A working gene is constrained by being useful, and is not free to mutate at random, as most mutations are likely to be deleterious. But if you duplicate a whole section of DNA containing that gene, the copy is free to change and maybe acquire a new role, without the host losing the function of the original. That’s how a primate ancestor of ours went from two-colour vision to three – a gene on the X chromosome encodes a protein that sits in the retina and reacts to a specific wavelength of light, and thus enables detection of a specific colour. By thirty million years ago, this had duplicated, and mutated sufficiently that blue had been added to our vision. This process has to happen during meiosis, where sperm and eggs are formed, if the new function is to be potentially permanent, as the new mutation will be inherited in every cell of the offspring, including the cells that will become the sperm or eggs. Primates seem prone to genome duplication, and the great apes particularly. Something like 5 per cent of our genome has come about from duplications of chunks of DNA, and about a third of that is unique to us. Duplicated

Consciousness is in our stars, our moons, and our stardust. It is in every cell of our developing bodies. The sperm and the egg are conscious.

Through his lenses Leeuwenhoek saw one-celled protozoa, blood cells, sperm cells, and many other “animalcules,” as he called them. In 1683, pressing against the limit of his ability to discriminate the fine structure of this microscopic underworld, Leeuwenhoek saw bacteria (derived from tooth scrapings), and he vividly described and drew relatively accurate pictures of them.

You can think of the human body as a set of transportation systems . . . Our reproductive system is a series of tunnels and tubes that transport egg and sperm cells from where they are made to where they need to go to create a pregnancy.

Making a human always takes the same three ingredients—an egg cell, a sperm cell, and a uterus. But just how the ingredients come together is a fascinating tale. With discoveries in science and medicine, we have insemination and IVF, along with sex, to bring babies into the world. Sometimes the ingredients that created us come from the same people who are raising us. Other times, we don’t share genetics with the people responsible for our care, such as when we are raised by stepparents, adoptive parents, or foster parents. This is also often true when donors and surrogates are involved.

You are comprised of 84 minerals, 23 elements, and 8 gallons of water spread across 38 trillion cells. You have been built up from nothing by the spare parts of the Earth you have consumed, according to a set of instructions hidden in a double helix and small enough to be carried by a sperm. You are recycled butterflies, plants, rocks, streams, firewood, wolf fur, and shark teeth, broken down to their smallest parts and rebuilt into our planet's most complex living thing. You are not living on Earth. You are Earth.

Making a human always takes the same three ingredients—an egg cell, a sperm cell, and a uterus. But just how the ingredients come together is a fascinating tale. Sometimes the ingredients that created us come from the same people who are raising us. Other times, we don’t share genetics with the people responsible for our care, such as when we are raised by stepparents, adoptive parents, or foster parents. This is also often true when donors and surrogates are involved.

Making a human always takes the same three ingredients—an egg cell, a sperm cell, and a uterus. But just how the ingredients come together is a fascinating tale. With discoveries in science and medicine, we have insemination and IVF, along with sex, to bring babies into the world. Sometimes the ingredients that created us come from the same people who are raising us. Other times, we don’t share genetics with the people responsible for our care, such as when we are raised by stepparents, adoptive parents, or foster parents. This is also often true when donors and surrogates are involved

Making a human always takes the same three ingredients— an egg cell, a sperm cell, and a uterus. But just how the ingredients come together is a fascinating tale.

cell, for example, has about 2 m of DNA—a length about 250,000 times greater than the cell’s diameter. Yet before the cell can divide to form genetically identical daughter cells, all of this DNA must be copied, or replicated, and then the two copies must be separated so that each daughter cell ends up with a complete genome. The replication and distribution of so much DNA is manageable because the DNA molecules are packaged into structures called chromosomes, so named because they take up certain dyes used in microscopy (from the Greek chroma, color, and soma, body) (Figure 12.3). Each eukaryotic chromosome consists of one very long, linear DNA molecule associated with many proteins (see Figure 6.9). The DNA molecule carries several hundred to a few thousand genes, the units of information that specify an organism’s inherited traits. The associated proteins maintain the structure of the chromosome and help control the activity of the genes. Together, the entire complex of DNA and proteins that is the building material of chromosomes is referred to as chromatin. As you will soon see, the chromatin of a chromosome varies in its degree of condensation during the process of cell division. Every eukaryotic species has a characteristic number of chromosomes in each cell nucleus. For example, the nuclei of human somatic cells (all body cells except the reproductive cells) each contain 46 chromosomes, made up of two sets of 23, one set inherited from each parent. Reproductive cells, or gametes—sperm and eggs—have half as many chromosomes as somatic cells, or one set of 23 chromosomes in humans. The Figure 12.4 A highly condensed, duplicated human chromosome (SEM). Circle one sister chromatid of the chromosome in this micrograph. DRAW IT Sister chromatids Centromere 0.5μm number of chromosomes in somatic cells varies widely among species: 18 in cabbage plants, 48 in chimpanzees, 56 in elephants, 90 in hedgehogs, and 148 in one species of alga. We’ll now consider how these chromosomes behave during cell division. Distribution of Chromosomes During Eukaryotic Cell Division When a cell is not dividing, and even as it replicates its DNA in preparation for cell division, each chromosome is in the form of a long, thin chromatin fiber. After DNA replication, however, the chromosomes condense as a part of cell division: Each chromatin fiber becomes densely coiled and folded, making the chromosomes much shorter and so thick that we can see them with a light microscope. Each duplicated chromosome has two sister chromatids, which are joined copies of the original chromosome (Figure 12.4). The two chromatids, each containing an identical DNA molecule, are initially attached all along their lengths by protein complexes called cohesins; this attachment is known as sister chromatid cohesion. Each sister chromatid has a centromere, a region containing

But your genes can also be different from those of your parents just through random mutation, which is the imperfect copying from one strand of DNA to another. It can literally be a cosmic ray from outer space that knocks into one of your genes and changes it. Genes sometimes jump from one place on the DNA molecule to another. These are called transposon genes. It could be that your parent’s eggs or sperm (or a plant’s ova and pollen) got messed with a little by some chemical. It could be radiation from some radioactive elements in Earth’s crust that caused a mutation. Sometimes viruses get into the reproductive cells of an organism and modify its genes. Virus manipulation can also be exploited deliberately—to adjust the genes of corn plants so they are tolerant of aggressive weed killer, for example.

In fact, it is not impossible that one day the sperm-less fertilization of eggs — based on triggering the genetic code present in any cell of the body — will become a reality.[131]

Andrew thought that it was strange that humans would choose the day of coming forth from the womb as the significant thing to commemorate. He knew something of human biology, and it seemed to him that it would be much more important to focus on the moment of the actual creation of the organism, when the sperm cell entered the ovum and the process of cell division began. Surely that was the real point of origin of any person! Certainly the new person was already alive - if not capable of independent functioning - during the nine months spent within the womb.

sperm and an egg meet, called fertilization, to make one cell called a zygote. That zygote doubles (divides in two) over and over to achieve 36 doublings (236 cells) over 270 days of pregnancy for a total of 68 billion cells at birth; that averages doubling about every 7.5 days. This growth happens in the lowest oxygen environment imaginable (the placenta delivers to the fetus a partial oxygen pressure of 30 millimeters of mercury (30 mm Hg), compared to the 100 mm Hg that the lungs deliver to adult cells). So how do fetal cells grow so fast with so little oxygen?