Indian sprinter Dutee Chand competes in women's competition; in 2014, Chand was found to have high levels of testosterone in her blood. The SRY gene is found on the Y chromosome; the SRY gene is 887 base pairs.
Guevedoce children have been studied in the Dominican Republic. DHT is more potent than testosterone in giving male characteristics to a person. DMRT1 is a gene that helps the testes develop. On the other hand, FOXL2 feminizes the body. Pogonomyrmex are "bearded ants."
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Guevedoce children have been studied in the Dominican Republic. DHT is more potent than testosterone in giving male characteristics to a person. DMRT1 is a gene that helps the testes develop. On the other hand, FOXL2 feminizes the body. Pogonomyrmex are "bearded ants."
Thanks for watching. Follow for more videos.
#cosmosspacescience
#throughthewormhole
#season7
#episode3
#cosmology
#astronomy
#spacetime
#spacescience
#space
#nasa
#spacedocumentary
#morganfreeman
#male
#female
#gender
Category
ЁЯУЪ
LearningTranscript
00:00Boy or girl? It's the eternal question.
00:07But that question may have more than two answers.
00:13Science is finding the line between male and female bodies is blurred.
00:20Identifying the hallmarks of a transgender brain
00:25and studying people who seem to change sex spontaneously.
00:32Are some people neither male nor female?
00:37Are there more than two sexes?
00:45Space. Time. Life itself.
00:52The secrets of the cosmos lie through the wormhole.
01:09Everyone who ever lived was created from the genes of one man and one woman.
01:17Those genes blended together to make a unique child.
01:21With dad's dark hair and mom's curls.
01:25Or with mom's lips that curl into dad's smile.
01:30One thing, however, isn't a blend.
01:34The child's sex.
01:37It's either male or female.
01:40But is there something in between?
01:44Many transgender people, their friends and families say there is.
01:50But what does science say?
01:53Today, that question is playing out in a very public arena.
01:58For more than 100 years, athletes have pushed themselves to the limit to be the strongest, the fastest.
02:11And for almost as long, some have been doing whatever it takes to gain that winning edge.
02:17But endocrinologist Richard Holt is watching them.
02:24He's a pioneer of tests designed to spot athletes seeking an unfair advantage.
02:30The difference between somebody winning and somebody not winning is absolutely tiny.
02:35We're talking about maybe less than 1%.
02:39There are a number of athletes who might be just that little bit away.
02:43And they think, well, maybe if I just take a little bit of extra, then I will be able to reach the pinnacle of the career.
02:51Richard's human growth hormone test debuted at the 2012 London Olympics.
02:56But lately, he's entered a more controversial arena.
03:00Verifying athletes' sexes.
03:03Indian sprinter Duti Chan grew up as a woman and runs against them.
03:11But on the eve of the 2014 Commonwealth Games, she ran into a problem.
03:18She was found to have high levels of testosterone in her blood and fell foul of the regulations.
03:27She was banned from competition.
03:29Men and women both make testosterone naturally, but in very different quantities.
03:34According to international athletic rules, Chand fell outside the female reference range.
03:41She did not fit the definition of a woman.
03:45Imagine we had two athletes, a man and a woman, and we looked at the two together.
03:50We'd see that, on average, the man would be taller than the woman.
03:53He'd have broader shoulders than the woman.
03:56He'd have bigger hands than the woman.
03:58Men, on average, have much more lean body mass than women.
04:03If you've got more lean body mass, you've got a stronger engine.
04:08To avoid men sneaking into women's events, sporting federations began in the 1960s to certify women as women.
04:17They did this the old-fashioned way, by visual inspection.
04:23But this led to controversy.
04:26Athletes felt the practice was indecent and disrespectful.
04:31Since the 2000s, some women have instead been subjected to testosterone tests.
04:41But a recent large study of more than 800 elite athletes found that testosterone tests can't always tell men from women.
04:50What they found was that there was about 15% of men that had testosterone levels that were below the typical normal reference range.
04:58And there were about 13% of women whose testosterone were above the upper limits of the female range.
05:05In other words, there's no clear dividing line between male and female testosterone levels.
05:10In fact, there's no evidence that naturally high testosterone even gives you a performance advantage.
05:17If testosterone was really key to athletic performance, what we would expect is that among men, men with the highest level testosterone were those men that were winning the races.
05:29But I can tell you, some of them had very, very low testosterone levels.
05:33And despite having very low testosterone levels, they were still capable of competing at the very, very highest level.
05:40Dutti Chand fought the ruling against her, claiming it was discriminatory to ban her for a naturally occurring condition.
05:50In 2015, she won back the right to compete.
05:56Testosterone screening for female athletes has been suspended for the moment.
06:01But there's no agreement on what should replace it.
06:04I think the best way of actually determining whether a woman should be able to compete as a woman is the way that she self-identifies.
06:12If she's always seen herself as a woman, regardless of what her testosterone levels are, I think she should be allowed to compete as a woman.
06:20Sporting federations are still wrestling with how to draw the line between male and female bodies.
06:26But Israeli neuroscientist Daphna Joel has been looking for tell-tale differences in another place.
06:39Our brains.
06:40There are many studies finding differences between men and women in brain structure, brain connectivity, brain function, and also in behaviors, attitudes, etc.
06:49But the question is whether these differences add up to create two types of people.
06:54Do the differences between the ways men and women behave trace back to physical differences in their brains?
07:01Science has asked this question for generations.
07:06In the 18th century, anatomists noticed that men, on average, had larger skulls.
07:13In the 19th century, they discovered that the brains of men tended to weigh more than those of women.
07:19These differences quickly became politicized.
07:23They started using this to explain female inferiority, when they discovered that the brains of males were, on average, larger than the brains of females.
07:32Then again, this was used to explain why women are not as intelligent.
07:36There's a long history of science being used to justify and maintain the social order.
07:42Today, we think we're too sophisticated to make that mistake.
07:47Studies show that more men than women like soccer.
07:51We now know that doesn't make soccer an exclusively male sport.
07:56But when we talk about the brain, we still fall back on male and female stereotypes.
08:01For example, scientists have found that, on average, a brain structure called the amygdala is larger in men.
08:10Because the amygdala is linked to aggression, you often hear people say aggression is a male trait.
08:16The idea that there is a male brain and female brain is so popular that people that write books about this get to be millionaires.
08:25These ideas depend on one big assumption, that you can look at any brain and tell whether it belongs to a man or a woman.
08:35Daphna set out to test whether this is really true.
08:38She analyzed MRI scans from more than 1,400 men and women.
08:43She wasn't looking at averages.
08:45She was looking at each individual brain.
08:48Imagine your brain is an ice cream sundae.
08:54You get something blue for each brain structure that follows the male pattern.
08:59You get something pink for each structure that looks female.
09:04Many different brain structures go into the sundae.
09:09We assume that all these differences add up one to the other to create one type of person.
09:14A man with a male brain and a woman with a female brain.
09:21Daphna's study put this idea to the test.
09:24If you're female, will every part of your brain look female in the MRI?
09:30If you're male, will every part of your brain look male?
09:37Looking at brains one by one, Daphna saw nothing like that.
09:42These sundae's should all look the same because they are all of women.
09:45But what we actually see when we look closely is that most people had a brain which was a mosaic, mosaic of features.
09:51The majority of brains has a mixture of both male and female characteristics.
09:56Brains do not have sex.
09:58And we should stop using the male brain, female brain idea to explain why men and women are fundamentally different because they are not.
10:06In body and mind, we are all mosaics.
10:11Pixelated images of both man and woman.
10:15There's no denying that most of us grow up knowing which sex we are.
10:21But on a deep genetic level, we could be wrong.
10:31Where does our sex come from?
10:34Well, like any biological trait, the answer lies in our DNA.
10:38There are two sex chromosomes.
10:42One is called the X, and its little sidekick is the Y.
10:47Usually, women have two Xs, and men have one Y and one X.
10:55But a small percentage of babies are born with chromosomes in neither of these arrangements.
11:01The more we learn about the biology of sex, the less it seems like there are only two sexes.
11:14Geneticist Eric Villain works with an unusual group of patients.
11:20They do not fit our normal definitions of male and female.
11:28One term for them is intersex.
11:31I see patients with intersex conditions.
11:35Their biological sex does not match their appearance, such as their genitals.
11:42And sometimes they're in between.
11:44Their genitalia are ambiguous.
11:47About one in a hundred people have some degree of intersex condition.
11:52That's roughly the odds of having green eyes or red hair.
11:56While those qualities are visible to the naked eye, some intersex people aren't even aware of their condition.
12:03In his research, Eric found one particularly striking case.
12:08So I had a patient, a young girl, 17 years of age.
12:11Let's call her Eileen.
12:13And she came to my office because she didn't have any periods.
12:17Unlike all her friends, month after month she was waiting.
12:21Nothing.
12:22Eileen looked like a completely typical girl.
12:26She was tall.
12:27She was good looking.
12:28She was well put together.
12:30Even though she looked completely female, there's one thing that was not working properly.
12:36She could not produce eggs.
12:38And she could not produce female hormones.
12:41We sent some tests for Eileen.
12:44And the first test we sent for were chromosomes.
12:47And that's when we discovered that she had an XY pair of chromosomes and not an XX.
12:53Eileen was actually male.
12:56At least according to her genes.
12:59The human genome is an incredibly complex molecule.
13:04It's the source of the many millions of instructions which our bodies follow as they grow.
13:10The determination of which sex we are is just one of them.
13:14In each cell of the human body, there are 46 chromosomes like this one, containing millions of base pairs.
13:24But only one has something to do with determining sex.
13:28Our 46 chromosomes come in 23 pairs.
13:33Half of each pair comes from our mother, the other from our father.
13:38Within the chromosomes, our genes determine everything from eye color to the shape of our earlobes.
13:44Hidden among these pillars of our existence is one pair of sex chromosomes.
13:50Their combination determines whether we become male or female.
13:55Women are XX, men XY.
14:00But if Eileen was male, why didn't she look male?
14:04Eric went looking for the root of the problem.
14:07We sent for another series of tests looking for mutations in genes important for sexual development.
14:14One of these tests looked for mutations in a critical gene on the Y chromosome called SRY.
14:23On the Y chromosome, there is this small gene called SRY that's only 887 base pairs, and it determines sex.
14:33It was once believed that many genes on the Y chromosome work together in the womb to make you male.
14:40But we now know that the tiny SRY gene does that job all by itself.
14:46If SRY doesn't work correctly, the child can grow up looking female.
14:52We identified one base pair that was different in Eileen.
14:57This one mutation was responsible for her being not a boy.
15:03Out of 3 billion base pairs in the human genome, a single one had switched places with the one beside it.
15:11It's called a point mutation, the smallest possible alteration that can be made to a gene.
15:19Since mutations can be inherited, Eric invited Eileen's relatives to come for testing.
15:25He found two more females who were genetically XY.
15:29Like Eileen, they had never had periods and could not bear children.
15:34Because of one tiny mutation, they'd lived as women for their entire lives.
15:41When it comes to SRY, the main sex-determining gene, there is no room for error.
15:47One base pair mutation and the sexual development switches from male to female.
15:54For this handful of patients, along with millions of intersex people around the world,
15:59learning the truth about their genes can mark the beginning of a difficult process.
16:04They're really ashamed of their situation, and that's something that I can't stress enough.
16:10Despite the fact that these conditions are rare, they're not unique.
16:15They're not alone, then the sense of shame disappears,
16:18and then they can embrace their conditions rather than be ashamed of it.
16:23Most of us can't imagine the anguish that the intersex 1% must go through.
16:28But some people have even more challenging transitions.
16:32They hit puberty, and their sex seems to suddenly switch.
16:39We all know that time changes us.
16:43First we grow taller, then a little shorter.
16:49We lose our baby fat, and then we get a little of it back.
16:55But for most of us, one thing doesn't change.
17:01Our sex.
17:03As we age, we learn to wear our masculinity and femininity like an old suit.
17:10But that's not true for everyone.
17:13Pediatric endoprenologist Chris Howard lives on 150 acres in South Carolina.
17:26In this grand laboratory of nature, he encourages his kids to study the birds and the bees.
17:33We live here with chickens and a horse and bees and soon-to-be goats.
17:40It allows kids to connect with nature.
17:43The eggs hatch, and then they grow up and become mature, male or female,
17:48and then they make more babies, and the circle of life continues.
17:52Chris' research focuses on the biological process of growing up.
17:59How girls become women, and boys become men.
18:03A few decades ago, some intriguing evidence emerged that not everyone follows those facts.
18:10Back in the early 70s, there was a rumor that circulated that there was a village in the Dominican Republic
18:16where girls turned into boys at the age of puberty.
18:20The villagers seemed to know about this.
18:22They had multiple generations, seven or eight generations that they could document at the time,
18:27to the point that they had created a terminology for it called guevedoces, which means penis at 12.
18:34Before their daughters hit puberty, the villagers trusted their eyes and raised them as girls.
18:43But when they hit puberty, sometimes things went a little haywire.
18:49Similar to humans, chickens go through puberty.
18:54Testosterone is what initiates chicken puberty and establishes sexual maturity, the ability to reproduce.
19:00To use this analogy, in guevedoces, a chick that appears to be coming a hen,
19:06takes on some of the secondary sexual characteristics that one would only see in a rooster.
19:11When researchers tested the guevedoces, they found high levels of testosterone.
19:17And their sex chromosomes were XY.
19:21Biologically, they were male.
19:24Puberty had somehow revealed their underlying genetic sex.
19:29But how?
19:30Let's use this egg for a moment to talk about human development.
19:35We'll pretend that this egg is a womb.
19:37Within it is contained the fetus and all the materials needed to make a male or a female.
19:45If we wanted to make a female, this would be the end of it.
19:48We're done.
19:49We can scramble this up.
19:50We can sunny side up.
19:51We can over medium.
19:52That is a girl egg.
19:53Making a female is a simple recipe.
19:56Just leaves nature's goodness alone.
19:59But male development calls for more ingredients.
20:02In a very early time in human development, we would need to add testosterone.
20:07And that will have a tremendous effect.
20:09But if this is all you do, your internal anatomy will be male, but no one will know it.
20:14In the gravidosis, this was the stage where male development went off course.
20:20They were missing a crucial extra ingredient.
20:23You need another more potent activator of maleness.
20:27And that would be a hormone called DHT.
20:31This hormone is at least 100 times as potent as regular testosterone.
20:36And is critical for what we call male development.
20:39In the womb, DHT is made from regular testosterone.
20:44It takes an enzyme called 5-alpha reductase to do this job.
20:50In a normal male embryo, DHT creates structures we associate with maleness.
20:56At the end of the process, a baby boy is born.
21:01In the gravidosis, a genetic mutation prevented them from making DHT.
21:07They looked female until puberty when a surge of testosterone
21:12finally transformed their bodies into male ones.
21:16This strange discovery led researchers to a deep psychological question.
21:21How will a male see himself if he is raised as a girl?
21:27We have these two terms, sex and gender.
21:30They're often used interchangeably.
21:32But to us in medicine, they are two distinct things.
21:35Sex generally refers to the physical appearance of an individual.
21:41Gender is something totally different.
21:43It's something sort of ethereal.
21:45It's this internal sense of I'm a male or I'm a female.
21:49Or I'm neither.
21:51Something in between.
21:54Well into the 20th century, gender was seen as something parents could assign to children.
22:01Raise a girl in a female role, and she will see herself as a female.
22:08But the children in this Dominican village shattered this idea.
22:13Of the gravidosis raised as female, 95% transitioned to live as male.
22:20This sort of challenged that prevailing view that we could assign a gender.
22:25We could assign sex, you know, how you would raise the child.
22:29But you could not really assign gender.
22:31That there's something internal, something innate about gender.
22:37Our mental sense of whether we are male or female is not just an idea we get from the influence of others.
22:46Gender is rooted biologically deep inside us.
22:51So what happens in our minds when our gender and our sex don't match?
22:57Biology says that sex is not as simple as male and female.
23:06Approximately one in 300 people identify themselves as transgender.
23:13Transgender people feel their biological sex doesn't match who they truly are up here.
23:20Which raises a fascinating scientific question.
23:24Why do body and mind disagree?
23:36Transgender people are becoming much more visible in recent years, thanks to evolving social norms.
23:43Many go to great lengths to alter their bodies and ask their families to accept a different version of them.
23:50But where does the urge to change one's body come from?
23:55Neuroscientist Ivanka Savick is trying to understand the roots of transgender feelings in the brain.
24:02She studies how we perceive our bodies and feel at home in them.
24:07This is a very complex process for the brain because it involves several different areas that have to do with cognition, self.
24:16Who am I?
24:17It's a very high level cognitive process.
24:21Ivanka believes this cognitive process might be different in transgender people.
24:26Transgender people, they look at themselves in the mirror every morning and feel uncomfortable because they of course recognize the image but they don't feel this is the image that represents them.
24:39In a way they see somebody else.
24:42As a neuroscientist, Ivanka knows that connecting with your own body is a complex mental ballet.
24:51Our visual world overflows with information, colors, forms, movements.
24:57But our brains impose a kind of order, identifying those things which are most important to us.
25:06It starts with the visual cortex, which takes in everything we see.
25:13That information flows to more specialized brain regions.
25:18One identifies bodies, another identifies faces.
25:23And yet another region, the temporal parietal junction, identifies whether those faces and bodies belong to us.
25:31But it takes one more region to pull all these ideas together.
25:36The brain's identity center, the prefrontal cortex, must conclude this image feels like me.
25:45This is the mental network that allows us to recognize our own bodies and feel at home in them.
25:51And it operates completely unconsciously.
25:54This own body perception is so automatic so we don't even consciously reflect upon it.
26:04I look at my hand, it's my hand.
26:08I look at my face, it's my face.
26:11To recognize and know ourselves is something we take for granted every day.
26:18But in some people, it may work a little differently.
26:24Many transgender people do not identify with the bodies they are born with.
26:29And in many cases, it doesn't seem to be a matter of choice.
26:33In many, many people who are transgender, this occurs very early during the childhood.
26:39And it's very strong.
26:40And that's why it's very important to take this seriously.
26:45Ivanka thought transgender people might see in their mind's eye a body that's different from their physical image.
26:52In an experiment, she showed transgender subjects photos of themselves.
26:58In some of these photos, she had suddenly altered their physiques.
27:03Many, many body images are presented during a very short time.
27:07And for each image, they have to determine how much is it me.
27:12Ivanka gave her subjects very little time to reflect.
27:17But they consistently identified with the photos that altered their outward sex characteristics.
27:23And they made their choices so quickly, Ivanka suspected the unconscious process of own-body perception was working differently for them.
27:33So, she used MRI imaging to look at the connections in their brains.
27:40Think about what it takes to make a self-portrait.
27:44It's a dialogue between what your eyes tell you and what you think should be there.
27:49That's not unlike the unconscious dialogue that goes on between regions of your brain.
27:55People with transgender feelings don't have any visual impairment.
27:59They don't see the world any differently.
28:03But when Ivanka looked at their brains, she noticed two regions that weren't communicating in the usual way.
28:09We could see that there was a weaker connection between the area of the brain that represents self and the area of the brain that represents the own body.
28:22It could somehow explain this perception of seeing own body, recognize own body, but at the same time feeling that this is not part of the self.
28:32The struggle to feel like yourself when you look at your own body is at the core of trans identity.
28:41Ivanka's research has uncovered the roots of this struggle in the brain.
28:46To live happier lives, transgender people often correct their physical appearance through hormone therapy or surgery.
28:56It's a tall order to switch sex anatomically, but new research is showing it could soon get easier.
29:06Because on a hidden level, our bodies are constantly trying to switch.
29:11Hermaphrodite, it's an animal that has both male and female sex organs, like these snails.
29:24When they mate, either one can take on the biological role of the male or the female.
29:31New research is revealing that we all might be hermaphrodites, in a sense.
29:37Down at the level of our cells, there's a war between male and female raging inside all of us.
29:51Geneticist David Zarkova looks at how cells in our reproductive organs choose to be one sex or the other, and whether they can change their minds.
30:00Our interest is in how sexual differentiation happens, so how cells come to be either male or female.
30:08And so what we do is we find genes that we think might play an important role in that process, and we break them and we see what happens.
30:17SRY is the gene on the Y chromosome that decides whether you'll become male or female.
30:22And if SRY has been active, male development occurs.
30:24But David and his team decided to look beyond SRY to another gene called DMRT1.
30:33DMRT1 helps the testes develop, but David wondered why it stayed active in adulthood.
30:40If the sex of male cells is supposed to be fixed before birth, why was this gene still working?
30:47David works on mice as stand-ins for humans, as their biology is very similar.
30:55And he did what geneticists do.
30:58He let mice grow to adulthood, then broke the DMRT1 gene to see what would happen.
31:05In this microscopy room, we look at mouse tissue samples and we use specific stains to ask whether male or female-specific proteins are active.
31:13The color scheme is simple.
31:16Green for male cells, pink for female.
31:20When David eliminated the DMRT1 gene, then looked at the gonads of his mice, he saw something surprising.
31:28You can see that there are still some male cells, such as these, but there are many, many more intensely pink-staining cells.
31:35Deleting just one gene caused the cells to change sex.
31:39Ovaries were developing in the bodies of males.
31:44And he found this process works in both directions.
31:49At first we didn't really believe it, because this was supposed to be a testis, but all of this expression of female-specific genes.
31:57And so we repeated the experiment, but it was clearly true.
32:00This testis was essentially directly transforming into something that was very much like an ovary.
32:04It's a discovery that shakes the very foundations of sex.
32:10The cells which make us male or female don't have to stay that way.
32:16Could a woman produce sperm to make a baby with another woman?
32:20And could a man produce eggs?
32:21We all start with genes that could pull us toward male or female.
32:31For the first six weeks in the womb, a tenuous balance exists.
32:37Neither side is winning.
32:39The embryo seems neither male nor female.
32:41But after six weeks, if the embryo has a Y chromosome, the SRY gene kicks into action.
32:50The gene called SRY is the difference maker.
32:54The SRY is anchor, the pro-male genes swing into action.
33:04Overwhelming their competition.
33:07Pulling the fetus to develop as male.
33:15With sex determination complete, SRY hands over the reins.
33:20DMRT1 sees to it that a male child remains male.
33:30But if DMRT1 should ever leave his post, a gene called FOXL2 will seize the opportunity
33:39and start working to make the body female.
33:43Like SRY, FOXL2 spurs other genes into action.
33:53One, two, three, four!
33:56Which overpower the male genes and start making female cells.
34:06We have this lifelong battle between DMRT1 and FOXL2
34:10over whether the gonad will remain male or will instead become female.
34:16This is really different from the way we thought about things previously.
34:19Dave's genetic tinkering found a battle of the sexes going on inside us that never truly ends.
34:25In theory, an adult human body can be coaxed to make opposite sex hormones.
34:30A new era of gender therapy is on the horizon.
34:37But consider the dark side.
34:41Could this technology be misused?
34:44Could people with anomalies in their sex chromosomes be forced to accept genetic alteration?
34:51To make them fit into traditional male and female modes?
34:54Children who are intersex may be coerced into being assigned to one sex or the other.
35:01This has been a historical problem.
35:04This technology could potentially make that worse.
35:07So it'll have to be used responsibly.
35:09On the other hand, this new knowledge offers immense hope for transgender and intersex people
35:15who want to transition from one sex to another.
35:18The ultimate goal of gender transformation would be to allow somebody to become a reproductive individual of the opposite sex.
35:26It's a ways off, but now there's some reason to think that it might be possible for two men to have a baby with one making sperm and the other one making eggs.
35:34Some day, our society may contain many new kinds of happy families.
35:39Our children may be born with more ways of changing their body's sex if it doesn't seem to fit.
35:48Sex could soon be more fluid than we ever thought possible.
35:53But the animal kingdom is already showing that our understanding of sex could evolve even further.
35:59These scientists are exploring a world where making babies needs more than one male and one female.
36:07Sex and gender were long seen as male or female.
36:17However you thought of yourself, you could only use one bathroom door.
36:22But we now know the gender you feel you are can disagree with your anatomy.
36:28As a society, we are beginning to accept that sex and gender can be male, female, both, or somewhere in between.
36:38But in the future, we may choose to make sex even more complex than that.
36:44Creating more than one type of male and female, and even more possibilities in between.
36:52Good morning.
36:53Hey.
36:54Would you like to get a colony out?
36:55Sure.
36:57Biologist Joel Parker and evolutionary ecologist Sarah Helms Cahan were once classmates.
37:12Now a tiny species has brought them back together.
37:16A species which could reveal where we ourselves are headed.
37:23Okay.
37:24Are you ready to touch them?
37:25Yeah, well, they don't get stuck.
37:27Remember?
37:28Yes.
37:29You're braver than I am.
37:31I remember you were always squeamish about this.
37:32Throughout the desert southwest, there are many different species of seed harvester ants.
37:40But one of the most common is Pogonomermix.
37:42It means bearded ant.
37:44Pogo meaning beard.
37:47It was here, in the Pogo's desert habitat, that Joel came across a paradox.
37:53He found two different species of Pogos, a red type and a black type.
37:58Their colonies looked normal, with reproductive queens and males and hordes of sterile workers.
38:06But the two species shared a mysterious quirk.
38:09If you mated a queen with a male from her colony, you wouldn't get all the offspring the colony needed.
38:16You would only get female reproductives.
38:19You wouldn't get workers.
38:21So where did those workers all come from?
38:23Did they fall from outer space?
38:25Or did their appearance on the scene have a more earthy explanation?
38:32It was a mystery Joel and Sarah were determined to solve.
38:36A normal ant colony gets started when a newly mated queen goes off after she mates and digs a little hole.
38:43She'll crawl into the hole, then lay eggs that will become the first generation of workers.
38:47Workers are the backbone of an ant colony.
38:53These sisters forage for food and maintain the nest.
38:58But they can't reproduce.
39:00Reproductive females come later, when the colony is established.
39:05They are cared for and fussed over like the future queens they are destined to be.
39:09You could think of them as princesses.
39:13And finally come the males, the colony's lowliest members.
39:19Males have a very sorry lot in the insect world.
39:23They're very small.
39:24They basically only have two functions in life, to fly and to mate.
39:27But mating for these two species is where the system appears to break down.
39:35Joel discovered that each species wasn't being faithful to its own kind.
39:40They were flying off to have flings with the species next door.
39:45In a pogo mating swarm, different couplings produce different types of offspring.
39:50When a female mates with her own species, she makes another reproductive female, a future queen.
39:59But to mate one of the much needed workers, she must mate with a male from the other species.
40:05Usually when you think of a sexual system, you think of males and females.
40:10With our ants, we have a situation where there's two different types of males and two different types of females
40:15that are required to keep this population going.
40:18So you can think of it as like one species then that has four different sexes.
40:25In a species with four sexes, there is more than simply male and female.
40:32Joel and Sarah believe this system helps ants in a colony become more specialized in their roles.
40:40And they think it offers a preview of what may happen with humans in the future.
40:44The thing that blows me away about ants is when you actually start looking at them from a biological point of view,
40:52they are more highly advanced evolutionarily than humans.
40:56Ants started farming a hundred million years before we did.
41:00They don't have to be taught how to farm. It's all in their genes.
41:03We have ranching. We keep cattle.
41:08Ants tend their own kind of cattle, which are tiny little insects called aphids.
41:13We have soldiers that we send out to fight our wars.
41:18Ants also have soldiers that they send out to fight their wars.
41:21Where ants have gone, humanity has followed.
41:31Joel and Sarah think it is happening again.
41:35Today, every human baby is made from the genes of just two people.
41:40But we are now experimenting with modifying the human genome, inserting genes from other sources.
41:48A baby made this way would have more than just two parents.
41:53I can't even think what our sexual system will be like when we start using some of these new technologies to put foreign DNA into our germline.
42:01But when that happens, how many parents are we going to have?
42:04I think we are going to move beyond the simple binary of mother and father.
42:10I can see it becoming more difficult to be able to easily define who is the parent of a given child.
42:22The poet Audre Lorde once wrote,
42:24It is not our differences that divide us.
42:29It is our inability to recognize, accept, and celebrate those differences.
42:35One day, we may find ourselves embracing a rainbow of different sex identities.
42:42Medical techniques could expand the definitions of sex and allow us to accelerate the evolution of our species.
42:50Perhaps the question isn't whether there are more than two sexes, but whether there are more possibilities than we ever imagined.
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