The Path Show Script Sarah "Welcome" Delivery Baby

"Life'south Greatest Phenomenon"

PBS Airdate: November 20, 2001
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NARRATOR: People do all sorts of things to go attention. And why? It may exist the terminal affair on his heed, simply this human'southward trunk is working toward this.

Whether we're thinking virtually it or not, our bodies desire to make babies. And our bodies are very skilful at information technology. Around the globe most 365,000 new babies get made every day.

But as ordinary as it seems, creating a new human is no unproblematic feat. Just retrieve of it. No affair who you are, once upon a time you looked like this. From a single cell you lot built a body that has one hundred trillion cells. Y'all made hundreds of different kinds of tissues and dozens of organs, including a brain that allows y'all to practice remarkable things.

How did y'all do it?

Today, we can look closer than always before: into the womb, into a cell, into the essence of life itself. Non merely can we see what's happening, but now we're beginning to meet how it happens—the forces that build the embryo, the molecules that drive this remarkable change. We're uncovering the most intimate details of how life is created, the secrets behind life's greatest phenomenon.

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Scientific accomplishment is fueled by the elementary desire to make things clear. Dart PCS is proud to support NOVA.

And by the Corporation for Public Dissemination, and by contributions to your PBS station from viewers similar you. Thank y'all.

NARRATOR: You might retrieve all the people on this beach are just working on their suntans. Only beneath all that sunscreen, nether the peel, at that place's a frenzy of activity. Without even thinking almost it, almost all the adults here are decorated trying to reproduce. They tin't help themselves. The urge to procreate is a fundamental part of life, not just for united states but for all life.

Why is this urge so universal? At least some arraign tin can probably get to this: Dna—the molecule that carries our genes, the chemical instructions for edifice our bodies and keeping u.s. alive, all wrapped up in a tiny winding staircase.

DNA has run the show for more than four billion years for ane principal reason: it'south very good at making copies of itself. The copies tin can get passed to a new generation in a couple of means.

If yous're a bacterium, you lot might exist into cloning—making exact replicas of yourself. All your descendents take the same DNA and, except for an occasional mutant, are just like you. Information technology's simple. It works. And genetically it's extremely boring.

It can besides exist dangerous.

If humans were all clones, anybody would accept the exact aforementioned allowed system, and one successful parasite could wipe u.s.a. all out.

Fortunately, there's sexual practice, the method of choice for 99.ix percent of the organisms on Earth more complex than bacteria. With sexual reproduction, two individuals each provide some DNA. Most animals put information technology into sperm or eggs. If the 2 can become together, a new existence will be created, one that'due south different from its parents and everybody else.

Where at that place'south sex activity, there's diverseness. And when it comes to survival of the fittest, variety has a definite advantage.

All this comes at a price. Sexual reproduction may exist popular, only it's also quite tricky. To get an idea of how catchy, simply have a peek inside a man's testicle.

It's packed with tiny tubes coiled into bundles. Stretched out they could cover one-half a mile. Inside all this tubing, the average man is churning out a thousand new sperm every second. That's about a hundred million new sperm every twenty-four hour period and more than 2 trillion over a lifetime. And here's the tricky office: each and every sperm is 1 of a kind, conveying a unique genetic parcel.

How is this possible? How can one person produce then many different combinations of genes? The answer lies in the very special way we make sperm and eggs, a process called "meiosis."

In most every cell of your body you lot have 30 thousand or more different genes, spread out on very long strands of Deoxyribonucleic acid called "chromosomes." Well-nigh cells have two versions of every gene on a total of 46 chromosomes. Exactly one-half of those, 23, came from your mom, and 23 came from your dad. They come up in pairs where the partners are very similar but not quite the aforementioned. The but time they get together is during meiosis.

Hither's how it works inside a testicle that'due south making sperm. Showtime, each chromosome makes an exact copy of itself, keeping it fastened at one point. They condense, creating an 10-shape. At present the chromosome partners assemble and the two, or actually iv, volition embrace. They cling and so closely, big chunks conveying whole bunches of genes get exchanged between the partners. The cell so divides twice, each fourth dimension pulling the pairs apart. The concluding outcome is a sperm or an egg jail cell with 23 chromosomes, one-half the normal number.

By itself, the jail cell is incomplete. Merely it yet holds incredible promise, considering every chromosome now carries a combination of genes that has never existed before.

All this gene shuffling means that within a single species, there tin can exist an enormous corporeality of variety. And the more diversity, the improve the odds are that someone will survive to create a new generation.

MELINDA TATE IRUEGAS: This is my mom and dad and your mom and dad.

SERGIO IRUEGUS: And my mom and dad on their wedding solar day. You lot definitely have your mom's eyes. And you tin run into I definitely accept my dad's eyebrows.

MELINDA TATE IRUEGAS: You lot practise accept your dad'due south eyebrows.

NARRATOR: Melinda Tate Iruegas and her married man, Sergio, are expecting their first infant.

SERGIO IRUEGUS: Here'southward Mom and Dad with me and my brother.

MELINDA TATE IRUEGAS: Yes.

SERGIO IRUEGUS: My sister hadn't come up along yet. But this is what our picayune male child might look like. That's me.

NARRATOR: Their unborn child carries a mixture of genes not just from them, but from all their ancestors.

SERGIO IRUEGAS: That's similar the spitting image. You expect then much like your mother here.

NARRATOR: Merely which genes got passed on from whom right now is anybody's guess.

SERGIO IRUEGAS: Because hither you are and this is what our little girl might look like. I wonder if the baby will have the feature eyebrows that come from my father's side of the family. Nosotros call them the Iruegas eyebrows.

MELINDA TATE IRUEGAS: Or that it won't accept my dad'due south nose.

SERGIO IRUEGAS: Your nose.

MELINDA TATE IRUEGAS: Nosotros talked about having children a lot. He would say, "Five, half-dozen." I was like, "Well, let's start with 1. Two, maybe three."

NARRATOR: In their efforts to pass on their genes, Melinda and Sergio pursued dramatically different strategies. Similar nigh men, Sergio has been constantly producing sperm since puberty.

Only Melinda created all her eggs when she looked like this, a fetus in her mother'south womb. Within a couple of months, she created several meg eggs. Then, the eggs began to die. At the age of 31, Melinda may but have a few chiliad left. But that'south okay, considering inside an ovary, as opposed to a testicle, it'due south quality, not quantity, that counts.

Every month, 1 of a woman's 2 ovaries selects an immature egg cell to lavish with attention. Hundreds of support cells tend the egg, feeding information technology until it grows fat. When it's ready, the whole entourage—the egg along with its helpers—oozes out of the ovary.

Waiting for them is the open end of the Fallopian tube, which leads to the uterus. Its tentacles capture the egg and pull information technology inside. The egg is swept along by muscular contractions of the tube, as well as the constant swaying of tiny cilia. The egg has everything it needs to start a new life, except for one affair: Dna from a sperm. And it has to get it fast. If the egg is non fertilized within a few hours it will die.

With sex, at that place will e'er be pressure to meet and impress a mate. When information technology comes to really choosing a partner, there'southward a lot to consider. For us, it might be somewhat more complicated than picking the one that smells best, simply there's no doubt that the process can be heavily influenced by chemistry, natural drugs that flood the brain.

When beloved is in the air, the body can undergo some dramatic changes. Signals from the encephalon speed upward the metabolism of glucose. As a upshot, body temperature rises, pare sweats, heartbeat and breathing get faster. In a man, hormones cue claret vessels to relax, allowing the spongy tissue in the penis to fill up with blood. At the height of sexual excitement, millions of sperm are squeezed out of storage and swept upwards by fluid gushing from several glands, including the prostate. The overflowing carries them into a fifteen-inch-long tube looping into the belly and and so out through the penis. Information technology'south but about a teaspoon of liquid, but it typically contains about three hundred one thousand thousand sperm.

They are immediately in peril. The vagina is acidic, so the sperm must escape or die. They start to swim, at least some of them. Even in a healthy man, 60 percent of the sperm can be less than perfect. Similar this one with two tails. For these guys, the journey is over.

But what well-nigh the residuum? What are the chances that one tiny sperm volition reach and fertilize an egg? Sperm are often portrayed every bit dauntless niggling warriors forging their way through hostile terrain to conquer the egg. Nothing could exist further from the truth.

For every challenge the sperm face, success is, to a great extent, controlled by the woman's body and even the egg itself.

Have the sperm'southward first obstruction, the cervix, passageway to the uterus. Near of the time, it's locked shut, plugged with mucous that keeps leaner and sperm out. But for just a few days a month, around ovulation, the mucous becomes watery and forms tiny channels that guide the sperm through.

Arriving inside the uterus, the sperm are yet about half dozen inches away from their goal—at to the lowest degree a two-day swim.But undulations of the uterine muscles propel the sperm into the fallopian tube within xxx minutes.

Even a sperm that reaches the tube in tape time has no guarantee of fertilizing an egg. There may be no egg there. Ovulation could still be days away.

It's the slowpokes, defenseless up in the cilia lining the tube, who may have a better chance. It's probably here that chemicals in the woman's body alter the sperm'south outer blanket. Just those sperm that are altered can become a date with the egg. The sperm are released gradually, over the course of a few days, then at any given fourth dimension only a couple hundred sperm volition move on.

If all goes well, then further up the tube they'll find the egg. But it's heavily chaperoned by support cells. And the chaperones are picky. Only some of the sperm are let through.

Those who go far volition face up yet another claiming. Underneath the cloud of cells, the egg itself is encased in a thick protein shell, called the "zona." To fertilize the egg, the sperm must break through the zona. But even the strongest can't exercise it by brute force alone. The egg demands a proper introduction. Proteins protruding from the sperm's cap must claw upwards precisely with a set of proteins on the egg's surface. If they match, the sperm is held fast and undergoes a dramatic transformation. It sheds its outer blanket, releasing powerful enzymes that deliquesce a hole in the zona, allowing the sperm to push button its mode through.

The final hurdle passed, the sperm nonetheless does non thrust its way into the egg itself. Rather, the membranes of the two cells fuse, and the egg draws the entire contents of the sperm inside.

MELINDA TATE IRUEGAS: I don't know. We weren't existence as careful as we should have been. And October came around and I was a day belatedly. And really I was having some other problems with my wrist. And we went to the doctor and the md had asked me...he's like, "Well, are yous pregnant?" You know, considering he wanted to do an ten-ray of my wrist.

SERGIO IRUEGAS: Yep.

MELINDA TATE IRUEGAS: And I said, "No." And and so I thought about it and I was like, "Well, I don't know." I decided that I meliorate check this out. And certain plenty, it was positive. And when he came dwelling, I was like...

SERGIO IRUEGAS: I could tell she had something to tell me.

MELINDA TATE IRUEGAS: And I was like, "Well you better sit down."

SERGIO IRUEGAS: It was something that we had discussed...

MELINDA TATE IRUEGAS: Yeah.

SERGIO IRUEGAS: ...but hadn't anticipated until about two more years downward the road. So when she told me...yep...I was ecstatic.

MELINDA TATE IRUEGAS: We were prepare. We were definitely fix even if information technology was a little early.

NARRATOR: Prepare or non, in one case sperm and egg get together they have their ain agenda: to create a feasible embryo. Their chances aren't not bad. It'south estimated that more 50 per centum of all fertilized eggs fail to develop. If information technology'due south going to survive, the egg has a lot of piece of work to do.

First, it orders the zona to lock out all other sperm. And then the egg must stop meiosis, expelling half of its chromosomes into this tiny pouch, called a "polar torso." With the door closed backside information technology, the unmarried sperm already within releases its precious cargo.

The sperm'due south 23 chromosomes stretch out in the roomy, welcoming egg. The chromosomes of sperm and egg arroyo each other and then the prison cell divides.

Since the moment the sperm entered the egg, 24 hours have passed. All this fourth dimension the fertilized egg is moving down the fallopian tube toward the uterus. Every few hours, the cells divide. Four...eight...xvi...gradually creating the edifice blocks needed to construct an embryo.

On rare occasions, the tiny cluster of cells splits into ii groups and creates 2 embryos—identical twins. Just nigh of the fourth dimension the cells stick together. They must consummate only the correct number of jail cell divisions before they make it in the uterus virtually five days after fertilization. What started equally a big single cell has divided into just over a hundred much smaller cells, merely they're still trapped inside the hard beat of the zona.

Now called a "blastocyst," the bundle of cells must practice two things to survive: suspension out of the zona and notice a source of nourishment. At the get-go of the sixth day, information technology orchestrates an escape. It releases an enzyme that eats through the zona, and the ball of cells squeezes out. Free at last, the blastocyst lands on the claret-rich lining of the mother'southward uterus. It has only passed one hurdle, simply is immediately presented with another.

For in fact it is at present in very grave danger. Stripped of its protective blanket, the blastocyst could be attacked by the mother's immune system as a foreign invader. White blood cells would swarm in to devour information technology. In its own self-defense, the ball of cells produces several chemicals that suppress the mother's immune arrangement inside the uterus, in effect, convincing the female parent to care for it similar a welcome guest.

Then it is gratuitous to get to work. Searching for nutrient and oxygen, cells from the blastocyst attain downward and burrow into the surrounding tissue. Eventually, they pull the entire bundle down into the uterine lining. And sooner or after, the mother volition notice.

MELINDA TATE IRUEGAS: Even brushing my teeth would make me...the minty season was just, like, gross. And it made me experience nauseous. And I would go upwards and I would effort to eat something. And if information technology...anything smelled off slightly, then it was...it fabricated me nauseous.

SERGIO IRUEGAS: My female parent has told me stories of how my father had gone through forenoon sickness. And of class that never really registered until the first time it started happening to me.

MELINDA TATE IRUEGAS: He literally got...he would get really, really nauseous and upset, and actually go physically ill sometimes.

SERGIO IRUEGAS: There was a couple of times when that...well, more a couple of times when that actually happened.

NARRATOR: Not everybody gets morning sickness. Sometimes months can go past before the mother gets whatever sense of the drama unfolding within her torso.

One milestone event takes place just two weeks later on formulation, when the blastocyst is about the size of a poppy seed. This is the moment when the cells start to organize themselves into an embryo. The procedure is called "gastrulation."

With animals like frogs, whose embryos develop inside transparent eggs, it's easy to see it in activity. Afterward the egg becomes a hollow ball of many cells, some cells dive into the centre, forming layers which will go along to develop into unlike organs.

In humans, gastrulation happens deep inside the mother'southward uterine lining, so information technology tin't be photographed. But nosotros think it works something like this:the blastocyst creates two ellipsoidal bubbling, one on tiptop of the other. Sandwiched between them is a thin layer of cells. These are the cells which one 24-hour interval may go a baby. At the start of gastrulation, some cells brainstorm moving toward the centre. And then they dive downwards, creating a new, lower layer. More cells plunge through, squeezing in betwixt, forming a 3rd. The cells in the three layers may non expect different, simply for each layer, a very different future lies ahead.

The lower cells are destined to class structures like the lungs, liver, and the lining of the digestive tract. The eye layer will form the heart, muscles, bones and blood. And the top layer will create the nervous organization, including the spinal cord and the brain, as well as an outer roofing of peel, and eventually, hair.

This is a homo embryo three weeks after fertilization. Less than a tenth of an inch long, its neural tube, the beginning of the nervous system, is already in identify. A couple of days layer, the acme of the tube is bulging outwards on its way to condign a brain. With the archaic brain cells exposed, we tin can see some are sending feelers, making connections to their neighbors.

As the days pass, changes proceed at a rapid-burn step throughout the embryo. Everywhere, cells are multiplying. And they're on the move. Some attain out to one some other, forming blood vessels. A heart begins to shell. As the embryo lengthens the precursor to the backbone forms. Groups of cells bulge out on the sides, the ancestry of arms and legs.

This is the embryo 4 and a one-half weeks afterwards fertilization. It is merely most a fifth of an inch long. The primitive backbone now curls into a tail, which will disappear in a few weeks. A big brain is developing, and on the side of the caput: an eye.

How does this happen? How does the embryo transform itself from a hulk of cells into different tissues and organs, and finally into a fully functional baby?

The secret, of class, lies in your genes—in your DNA. Within near every cell in your body, y'all take the same 46 chromosomes, carrying the same genes. Just not all the cells in your torso are the same. Nerve cells, blood cells, cells lining your intestine, they all look different and they practise different jobs.

That'south because in each of these cells different groups of genes are turned on. And when a cistron is turned on, it tells the jail cell to construct a particular poly peptide.Proteins are the molecules that build your body—like collagen, a cobweb that makes up much of your pare, tendons, and bones, or keratin in your pilus. Crystallin is the protein that helps make the lens of your eye clear.

Some proteins practice piece of work. Actin and myosin movement musculus fibers. Hemoglobin in the blood carries oxygen from the lungs to the rest of the trunk.

So when the embryo is developing, how does a prison cell plow on the right prepare of genes and create the right proteins?

Function of the reply seems to be location. Once the basic body plan is established, with a head on 1 terminate, back and front end, and left and correct sides, cells seem to know exactly where they are and what they are supposed to become. This is because cells talk to each other in the grade of chemical messages.

Chemicals in one cell can trigger a reaction in the prison cell side by side door that tin can spread to the cell's nucleus and turn genes on or off. Just what's really going on in there? How does a gene get turned on?

If all the DNA in a single cell were stretched out, it would be near six feet long. But it's all wound upward very tightly, coiled effectually balls of protein. For a gene to be turned on, something has to come in and loosen up the right section. Then the cell'south mechanism tin can latch on and read the DNA, the get-go step on the long road to edifice a protein. Those molecules that can turn genes on play a fundamental function in every aspect of development, including the process that transforms the embryo into a male child or a daughter.

SERGIO IRUEGAS: We didn't desire to know. Nosotros wanted to do it, I guess, the old fashioned way.

MELINDA TATE IRUEGAS: Well, you kind of wanted to know. We did a wedding ring test, where you took a piece of your hair and the nuptials ring and you hold it over the belly and if it moves one manner in a circumvolve, and then information technology's a girl; if information technology moves in a straight line it's a boy. And that said it was a girl.

And in that location was a point when we went into the ultrasound where I was waffling. Information technology was like, "Well, we could wait. At this very moment we could wait and nosotros could find out." And I didn't say anything.

SERGIO IRUEGAS: See...but...I was trying to exist strong because she was very determined nigh not...

MELINDA TATE IRUEGAS: I said, "No, no, no."

NARRATOR: Past the time most ultrasounds are done, around 18 weeks or and so, doctors can sometimes make out the sex. But in the early weeks it'southward impossible.

Have a await at a seven-calendar week-old embryo. Endeavor to guess what sexual practice information technology is. Think it's a boy? Believe information technology or not, this is not a penis, at least not yet. It might become one, just it could just as easily turn into a clitoris, the female sexual activity organ. At this stage boys and girls look exactly alike.

And not just on the outside. Inside, there are ii gonads which could get testicles or ovaries. And at that place are two sets of tubes, one in case it's a boy, the other for a girl.

Of course in that location is i way to tell the difference: look at the chromosomes in a prison cell from the embryo. One pair amid the 23 determines sex. An embryo with two 10 chromosomes ordinarily becomes a girl. If one of those Xs is a Y, it will virtually likely be a boy.

Recently, scientists came up with a good idea of how this works. There are only nigh 30 genes on the Y chromosome. One of them is called SRY. This cistron seems to function only once in a lifetime, late in the sixth week of embryonic development. And just in ane place, the gonad.

SRY turns on for a twenty-four hour period or two, and the cells churn out its protein. But in that short time, SRY sets off a chemic chain reaction, turning on other genes, eventually turning the gonads into testicles, which brainstorm to make testosterone. Testosterone travels throughout the torso. If it reaches the genitals so the cells hither volition build a penis.

But if there are two 10 chromosomes and no Y, different genes become turned on and the gonads become ovaries. The embryo becomes a baby girl.

This is the power of genes, creating cascades of chemical reactions, defining the form and function of all the cells in your body.

Sometimes genes send the message to multiply and grow, equally with the arm and leg buds. Sometimes the message is to die, as information technology is a few days after, to the cells betwixt the fingers. As the weeks pass, the embryo's genes ship billions of individual messages, constructing new kinds of cells and edifice organs and limbs.

2 months afterward fertilization, the embryo is at present called a fetus. Almost all its organs are in identify though they're non working still. The whole fetus is but over an inch long and weighs less than a third of an ounce.

Over the side by side six and half months, it volition grow almost four hundred times larger and ready for nascence. All of this demands a constant supply of nutrients.

MELINDA TATE IRUEGAS: Serge was a little frustrated 'cause he thought he was going to be able to leave and go me any I craved and whatever I wanted. And I had the problem of I didn't want anything or crave anything until I smelled it. And I had to smell my food before I would eat it. I could cook a whole meal, and if it didn't smell right when I was done with it, you know, just because I put the wrong spice in there or something, then I couldn't consume it.

SERGIO IRUEGAS: Well, what near this place here? Let's check out the menu.

MELINDA TATE IRUEGAS: No.

SERGIO IRUEGAS: No?

MELINDA TATE IRUEGAS: No.

SERGIO IRUEGAS: We would become out on walks sometimes, just around in the Square.

MELINDA TATE IRUEGAS: No.

SERGIO IRUEGAS: No?

MELINDA TATE IRUEGAS: That'southward non going to work.

SERGIO IRUEGAS: She would have to smell information technology outset. Just see what caught her fancy at that time.

MELINDA TATE IRUEGAS: Yeah.

SERGIO IRUEGAS: Aye?

MELINDA TATE IRUEGAS: Yeah.

SERGIO IRUEGAS: As soon every bit it did, then that's where we would go.

MELINDA TATE IRUEGAS: And that lasted throughout my entire pregnancy.

SERGIO IRUEGAS: How is information technology?

MELINDA TATE IRUEGAS: Garlicky. Yum.

SERGIO IRUEGAS: Baby likes it?

MELINDA TATE IRUEGAS: Yeah. I'thou pretty hungry. I'm withal like that. I still actually want to smell my nutrient, and if I smell something and I'yard just like, "Oh, I accept to take that and I accept to have it now."

NARRATOR: Information technology's no surprise that Melinda might be especially hungry. The fetus she's conveying has just one source for all the raw materials it needs to grow into a baby: Melinda's blood, which is systematically raided with the aid of the placenta.

The placenta began to form as shortly equally the blastocyst burrowed into the female parent'southward uterus, and in the early on weeks it dwarfed the embryo. The underside of the placenta is covered with thousands of tiny projections, called "villi" which prevarication in pools of the mother's blood. Without e'er mixing the blood of mother and child, the villi catch oxygen and nutrients. The enriched blood flows about a foot and a half through the umbilical string, dorsum to the fetus, whose heart beats about twice equally fast as an adult'due south.

The heart is i of the few organs that really work during the primeval weeks of evolution. Simply with other organs, function comes later. With the heart, although the retina and lens are well-formed by the ninth week, the fetus doesn't respond to low-cal until the fifth or 6th calendar month.

And the same for the ear. The outer ear chop-chop takes shape, but the fetus can't hear yet. Sound conduction relies on the tiny bones of the inner ear, and most of the bones in the fetus start out as cartilage. By the 4th month, hard bone tin be seen forming in the mitt and the leg. Finally, after five months, the process is complete in the inner ear. And then, the fetus begins to hear audio.

SERGIO IRUEGAS: I would sing songs, right on her belly, just and so that it could hear my phonation and get to know my vocalism. But there was...

MELINDA TATE IRUEGAS: And what else? And brand whale noises.

SERGIO IRUEGAS: Yeah. I of the get-go times I did that the baby seemed to move its hand beyond her abdomen and kind of touch my lips. Or at to the lowest degree I like to recollect information technology was a hand, saying hello or something.

MELINDA TATE IRUEGAS: And I even play music. You lot know, I wanted to see what would happen to what different kinds of music. And, you know, Mozart, yous know...was mellow...kind of made some movements. And so I put salsa music in and it but started kick, near in rhythm. And then information technology was keen.

SERGIO IRUEGAS: It had a particular beat that it likes.

MELINDA TATE IRUEGAS: Yes.

NARRATOR: Inside Melinda's belly, a remarkable transformation has taken place, starting with the moment egg and sperm met. Within the womb, the first few weeks are the nigh dramatic. Later in pregnancy, when the mother's body seems to exist changing the nearly, life in the womb tin appear, well, a bit uneventful.

All the organ systems are in identify, so during the final trimester the fetus's principal chore is to grow. But a few crucial events are unfolding beneath the peel. Fat deposits are forming, building reserves the infant volition rely on later nascence. Only even more importantly, fat is getting laid downwardly in the brain.

In the 6th month, genes in the brain order the industry of a fat substance called "myelin," which wraps around the long connections between brain cells. This fatty covering allows nerve impulses to travel upward to 100 times faster, greatly enhancing brainpower. The process volition continue for years after the baby is born.

The encephalon's hunger for fat in the last trimester puts an enormous strain on the mother. Over the course of the pregnancy, her trunk has increased its own claret supply past most 50 percent, all for the sake of the rapidly growing baby. Only late in pregnancy, the babe's need for fatty becomes and so great the mother can't keep upwardly. If it stays inside, the babe volition begin to starve. Somehow, it'due south got to get out.

MELINDA TATE IRUEGAS: I've only had, like, one feet attack. And information technology was the moment I was in the bathroom and I just had the thought of, like, "How'southward this baby going to go out? I just don't think he'due south going to brand it out." And I hadn't really thought about it up until that very moment, where I was just like, "No."

SERGIO IRUEGAS: I dearest you.

NARRATOR: Giving nascence is ane of the near astonishing experiences a woman can have. It can also exist one of the most painful.

SERGIO IRUEGAS: It'southward starting to get downward.

SHIRLEY TATE (Melinda Tate Iruegas's mother): Remember? Remember almost being in that garden.

NARRATOR: Again and again the uterus contracts as the neck opens upwardly. The tiny passageway that in one case allowed the archway of a single file of sperm at present must widen to about four inches to accommodate a baby's head.

Human births are far more unsafe than those of other mammals or fifty-fifty other primates. The human brain is three to four times bigger than an ape'due south brain. And the pelvis is narrower to let u.s. to walk upright. A human baby has to become through considerable contortions to make it through the narrow opening. Sometimes, there just is not enough room.

If that happens today, Melinda'southward baby can be delivered by caesarian department. Merely not long ago, before the rise of modern surgery, death was a mutual outcome for the baby and the mother.

SERGIO IRUEGAS: I tin can't help just experience a little guilty that I'thou responsible for this, but information technology's part of the natural cycle of life. And I just desire to be there in whatsoever mode that I tin can to support her through this whole process.

NARRATOR: Because of the pain and danger of human labor, nosotros regularly requite nascency in the presence of others. Today, at iv:25 a.m., Melinda's parents, along with Sergio, will have the privilege of witnessing firsthand this extraordinary event—life's greatest phenomenon.

NURSE: Catch it once again. All correct. That'south it. One more than time...push it correct down for more...oh skillful, good, practiced.

ED TATE (Melinda Tate Iruegas'due south begetter): A life! A new life! Expect at that little infant!

SHIRLEY TATE: Oh, a picayune penis! Information technology'southward a boy!

SERGIO IRUEGAS: Look at our little male child.

MELINDA TATE IRUEGAS: Hi. I was wondering who yous were. Yous're so handsome.

SERGIO IRUEGAS: We've been wondering who y'all were. We've been playing with yous.

MELINDA TATE IRUEGAS: Hi. Oh, there you go.

SERGIO IRUEGAS: I love that little yawn.

MELINDA TATE IRUEGAS: Wake up.

On NOVA's Web site, follow along in existent time every bit an expectant mother chronicles the joys and challenges of her final months of pregnancy and the birth of her baby, on PBS.org or America Online, Keyword PBS.

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Product CREDITS

Life's Greatest Phenomenon

Medical Photography
Lennart Nilsson

Narrated by
John Lithgow

Written by
Julia Cort

Director of Photography
Sven Nykvist

Produced for NOVA by
Julia Cort

Edited past
Dick Bartlett

Music
Ray Loring

Animation
rhed studio

Additional Animation/Embryonic Imaging
Bradley Smith

Product Assistants
Jennifer Callahan
Christian Rodriguez

Photography
Brian Dowley
Rolf Lindström

Sound Recordists
John Cameron
Erik Reisner

Online Editor
Will Hearn

Colorist
Gary Chuntz

Sound Mix
John Jenkins

Scientific Advisors
Lars Hamberger
Johan Ericson
Kerstin Hagenfeldt
Lars Holmgren
Ulrik Kvist
Hugo Lagercrantz
Urban Lendahl
Jonas Muhr
Åke Seiger
Anita Sjögren
Johannes Wilbertz
Harvey Fineberg
Douglas Melton
Janet Michaud
David Page
Michael Pinette
Doug Powers
Elizabeth Robertson
Hazel Sive
Meredith Small

Archival Material
Cells Alive!
Clouds Loma Imaging
Getty Images/The Epitome Bank
Alexey Khodjakov
National Geographic Moving picture Library
Natural History New Zealand Limited
Jeremy Pickett-Heaps, Cytographics
Provision AB
Conley Rieder
Rotebro Filmservice AB
Sekani Moving Ideas
Streamline Films, Inc.
Survival Anglia Limited
Sveriges Television AB
Visuals Unlimited, Inc.
Wild Visuals

Special Thanks
Danderyd Infirmary
Göteborg University
Huddinge University Hospital
Karolinska Institute
Sahlgrenska University Infirmary
Sophiahemmet Hospital
University of Lund
Uppsala University Infirmary
Eastman Kodak Company
Portia Brockway
Patricia Campbell
Mark Cooper
Leonard D'Amico
Harvard-Vanguard Medical Assembly
Sylvia Fine
Clarissa A. Henry
Charles Lee
Cynthia Morton
Mt. Auburn Hospital
Michael O'Connell
Picante Mexican Grill
Brian Price
University Lutheran Church

For Erikson & Nilsson Productions:

Production Supervisor
Lars Rengfelt

Drama Managing director
Mikael Agaton

Assistants to Lennart Nilsson
Jan-Åke Andersson
Klaus Biedermann
Mike Mixoff
Lars Pettersson
Malin Rohdin
Abdalla Saleh

Location Director
Anika Beclijevski

Actors
Lea Boysen
Henrik Dahl

Special Advisor
Catharina Nilsson

Controller/Project Manager
Madeleine Von Rohr

Assistant Producer/Editor
Lars Wiberg

Executive Producer/Writer
Bo G Erikson

For NOVA:

NOVA Series Graphics
National Ministry of Design

NOVA Theme
Mason Daring
Martin Brody
Michael Whalen

Mail service Production Online Editor
Mark Steele

Closed Captioning
The Explanation Center

Production Secretaries
Queene Coyne
Linda Callahan

Publicity
Jonathan Renes
Diane Buxton
Katie Kemple

Senior Researcher
Ethan Herberman

Unit of measurement Managers
Sarah Goldman
Jessica Maher
Sharon Winsett

Paralegal
Nancy Marshall

Legal Counsel
Susan Rosen Shishko

Business organisation Manager
Laurie Cahalane

Postal service Production Assistant
Patrick Carey

Associate Producer, Mail service Production
Nathan Gunner

Postal service Production Supervisor
Regina O'Toole

Mail service Production Editors
David Eells
Rebecca Nieto

Supervising Producer
Lisa D'Angelo

Senior Science Editor
Evan Hadingham

Senior Serial Producer
Melanie Wallace

Managing Manager
Alan Ritsko

Executive Producer
Paula S. Apsell

A NOVA Product by ERIKSON & NILSSON Production in association with WGBH/Boston and ZDF Germany, ARTE French republic and Germany, RAI three Italy, NHK Japan, BBC OPEN UNIVERSITY England, SVT1 Sweden, NRK Norway, DR Tv set Kingdom of denmark, YLE1 Finland, RUV Iceland