The Science Of Sexual Orientation (Mega Barf Alert!)

(CBS) There are few issues as hotly contested — and as poorly understood — as the question of what makes a person gay or straight. It's not only a political, social, and religious question but also a scientific question, one that might someday have an actual, provable answer.

The handful of scientists who work in this under-funded and politically charged field will tell you: That answer is a long way off. But as Lesley Stahl reports, their efforts are already yielding tantalizing clues. One focus of their research is twins.

--------------------------------------------------------------------------------

The bedrooms of 9-year-old twins Adam and Jared couldn't be more different. Jared's room is decked out with camouflage, airplanes, and military toys, while Adam's room sports a pastel canopy, stuffed animals, and white horses.

When Stahl came for a visit, Jared was eager to show her his G.I. Joe collection. "I have ones that say like Marine and SWAT. And then that's where I keep all the guns for 'em," he explained.

Adam was also proud to show off his toys. "This is one of my dolls. Bratz baby," he said.

Asked if he went to school like that, Adam says, "Uh-huh. I just showed them my nails, and they were like, 'Why did you do that?'"

Adam's behavior is called childhood gender nonconformity, meaning a child whose interests and behaviors are more typical of the opposite sex. Research shows that kids with extreme gender nonconformity usually grow up to be gay.

Danielle, Adam and Jared's mom, says she began to notice this difference in Adam when he was about 18 months old and began asking for a Barbie doll. Jared, meanwhile, was asking for fire trucks.

Not that much has changed. Jared’s favorite game now is Battlefield 2, Special Forces. As for Adam, he says, "It's called Neopets: The Darkest Faerie."

Asked how he would describe himself to a stranger, Jared says, "I'm a kid who likes G.I. Joes and games and TV."

"I would say like a girl," Adam replied to the same question. When asked why he thinks that is, Adam shrugged.

"To me, cases like that really scream out, 'Hey, it's not out there. It's in here.' There's no indication that this mother is prone to raise very feminine boys because his twin is not that way," says Michael Bailey, a psychology professor at Northwestern University and a leading researcher in the field of sexual orientation.

Psychologists used to believe homosexuality was caused by nurture — namely overbearing mothers and distant fathers — but that theory has been disproved. Today, scientists are looking at genes, environment, brain structure and hormones. There is one area of consensus: that homosexuality involves more than just sexual behavior; it’s physiological.

Bailey and his colleagues set up a series of experiments in his lab at Northwestern University. In one study, researcher Gerulf Rieger videotaped gay and straight people sitting in a chair, talking. He then reduced them visually to silent black and white outlined figures and asked volunteers to see if they could tell gay from straight. The idea was to find out if certain stereotypes were real and observable.

Based on physical movement and gestures of the figures, more often than not, the volunteers in the study could tell a difference.

"So, is the conclusion that gay people do in fact move differently?" Stahl asked Rieger.

It's not true 100 percent of the time; it is true on average. The researchers also studied the way gay and straight people talk, and they found differences on average there too.

This research is controversial. Some say it is reinforcing stereotypes. But to Bailey, the stereotypes suggest there's a feminizing of the brain in gay men, and masculinizing in lesbians. Ironically though, when it comes to their sex lives, he says gay and straight men actually have a lot in common.

"Straight men tend to be shallow in terms of focusing on looks. Gay men are shallow, too. Straight men are more interested than straight women in having casual, uncommitted sex. Gay men are like that, too," says Bailey.

"One has the impression that gay men are much more inclined toward casual sex than straight men," Stahl said.

"They're just more successful at it, because the people they're trying to have sex with are also interested in it," Bailey explained.

"But don't you find this interesting that the one big area where gay men are more like straight men is in sex? I mean, that is…both amusing and odd," Stahl said.

"It suggests that whatever causes a man to be gay doesn't make him feminine in every respect. There must be different parts of the brain that can be feminized independently from each other," Bailey replied.

But how and when does this feminizing occur? If the differences were already apparent in childhood, that would point to an early, perhaps even genetic origin — and that's what Bailey and Rieger are testing in a new study using childhood home movies.

In the study, volunteers were asked to rate each child's femininity or masculinity. Stahl took the test and rated two girls highly feminine.

When shown video of a toddler girl running a truck off of a table, Stahl observed, "She's really not girly. Isn't that interesting? She’s not girly."

She also observed differences in two boys, one of whom would grow up to be straight, while the other is now gay.

If you can spot a child's future sexual orientation before the child even knows he or she has one, doesn't that prove it's genetic? Studies have shown that homosexuality runs in families. So genes must be the answer. But then the researchers tell you identical twins can have different sexual orientations.

60 Minutes found identical twins Steve and Greg Lofts in New York. They had the same upbringing, have the same DNA — and yet Greg is gay and Steve is straight.

When people meet the twins and find out one of them is gay, Greg says people have asked if he's sure, and how it can be. "Everyone is curious about that," he says.

There were signs, even when they were little kids. Their mother told Stahl that Steve loved sports and the outdoors while Greg liked helping out in the kitchen. But it wasn't until high school that Steve became convinced Greg was gay.

Asked if he said anything to his brother, Steve says, "I did actually. And I think the way I worded it was something like, 'You know, Greg, if you're gay, it's OK with me. And I'll still love you the same.' And he gave a very philosophical answer. He said something like, 'Well, I love the soul of a person and not the physical being.' And in my mind, I was like, 'Yep, he's gay.'"

"What it proves is it's not completely genetic. They have the same genes," says Bailey.

"That's environment. But that's not the only environment. There's also the environment that happens to us while we’re in the womb. And scientists are realizing that environment is much more important than we ever thought it was," Bailey explained.

A newborn rat pup in the lab of Dr. Marc Breedlove at Michigan State University, may, oddly enough, hold important clues to what happens in the womb.

Dr. Breedlove says he can take a male rat and make it behave like a female for the rest of its life, and vice versa for a female, just by altering the hormones it's exposed to at birth. Because rats are born underdeveloped, that's roughly the same as altering a third-trimester human fetus in the womb. But first, he said, Stahl would need a crash course in rat sex.

Dr. Breedlove explained that male rats, including one he showed Stahl called "Romeo," will mount any rat that comes their way. In the mating process, the female performs something called lordosis, where she lifts her head and rump.

If Romeo goes after a male, Dr. Breedlove says the male will seem profoundly indifferent.

But Breedlove says he can change all that. He gave a female rat a single shot of the male sex hormone testosterone at birth. Now grown up, she will never perform lordosis.

"I wouldn't say that these are gay rats. But I will say that these are genetic male rats who are showing much more feminine behavior," he explained.

"That's exactly the question that we're all wondering. This business of testosterone having such a profound influence. Does that have some relevance to humans?" Breedlove said.

While biologists look at hormones for answers about human sexuality, other scientists are looking for patterns in statistics. And hard as this is to believe, they have found something they call "the older brother effect."

"The more older brothers a man has, the greater that man's chance of being gay," says Bailey.

If this comes as a shock to you, you’re not alone. But it turns out, it’s one of the most solid findings in this field, demonstrated in study after study.

And the numbers are significant: for every older brother a man has, his chances of being gay increase by one third. Older sisters make no difference, and there's no corresponding effect for lesbians. A first-born son has about a 2 percent chance of being gay, and the numbers rise from there. The theory is it happens in the womb.

"Somehow, the mother's body is remembering how many boys she's carried before," says Breedlove. "The favorite hypothesis is that the mother may be making antibodies when she sees a boy the first time, and then affect subsequent boys when she carries them in utero."

"And if you think about it, a woman who's carrying a son for the first time, she is carrying a foreign substance," Breedlove replied. "There are some proteins encoded on his Y chromosome that her body has never seen before and that her immune system would be expected to regard as 'invaders,'" he added.

"One of the things we've only found out lately is that older brothers affect a boy only if the boy is right-handed," Breedlove said. "If the boy is left-handed, if his brain is organized in a left-handed fashion, it doesn't matter how many older brothers he has, his probability of being gay is just like the rest of the population."

You can give yourself a headache trying to apply all the theories to real people. Greg and Steve Lofts both are right-handed, and they do have an older brother, so maybe that's why Greg is gay. But they also have several gay relatives, which suggests it could be in the genes, except where does that leave Steve?

Then there's the question of how something in the womb could affect one twin but not the other. There are many more questions at this point than answers, but the scientists 60 Minutes spoke to are increasingly convinced that genes, hormones, or both — that something is happening to determine sexual orientation before birth. Adam has come up with his own theory.

"I was supposed to be a girl in my mom's stomach. But my mom wished for all boys. So, I turned into a boy," Adam explained.

"Do you think there was anything that you could have done that would have changed Adam?" Stahl asked Adam and Jared's mom Danielle.

"I could have changed Adam on the outside to where he would have showed me the macho boy that I would want as a boy. But that would not change who he is inside. And I think that would have damaged him a lot more," she said.

Stahl asked both boys if they are proud of the way they are, and both boys gave her big nods.

Here is something to ponder on genetics. God said the sins of the father are passed on to his offspring. That made absolutely no sense to me until we learned more about genetics. If it turns out that destructive and addictive behaviors like boozing is genetic, why would not sex addictions be passed on genetically?

I strongly suspect that the vast majority of sexual mis-orientation occurs because of issues between the person and one of his/her parents. I'm not a child psychologist, but experiences during the formative childhood years clearly have a strong influence on the rest of a person's life.

Have there been any studies to look at sexual mis-orientation vis a vis parental relationships (divorce, single-parent home, emotional, psychological, sexual or physical abuse, etc.)? That seems to me to be where the real action happens.

Isn't is possible, however, that the chemical imbalance can have genetic causes?

Such is termed a hypothesis -in the case of this subject article generally and in the case of a genetic cause specifically for the homosexual disorder - an unproven hypotheis...

The elite media treat kids like Adam the same way the Sioux used to around the time of first-contact with Europeans. If a Sioux young boy chose to play with a doll, he was dressed in women's garb, sodomized by some of the men, and treated as a woman for the rest of his life.

Was this done because the young boy was genetically "gay"? No. It's simply a barbaric ritual that was later discarded. Just like scalping and cannibalism.

Our own barbaric culture has brought back sodomy and raised it to the level of a civil right. How long before they bring back scalping and cannibalism, too?

Jeeeeez, what were they thinking when they allowed him to do that crap?

The parents are obviously part of the problem. Then again, if they had done what most normal parents do and nipped this stuff in the bud at age 4, they wouldn't have had a reason to invite Leslie Stahl into their home for their 15 minutes of fame, would they?

Can I ask a question here because I would be interested in hearing the membership's responses.

If it was proven fact down the line by the scientific community that homosexuality was hormonally induced, not genetically, nor a disorder of the mind - would the people here accept it as a physical anomaly - one which could not be affected or changed by the human, unless during the course of study, it is found that hormonal influence could be altered through application of medical treatment (even then not guaranteeing successful change)?

In other words if is a natural aberration in some to be born with a distinct hormonal impairment or one in which sexual identity does not equate with physical appearance..
could religious groups accept the scientific fact at some time in the future - or will homosexuals always be charged with "change" or "rejection"?

In other words if is a natural aberration in some to be born with a distinct hormonal impairment or one in which sexual identity does not equate with physical appearance.

The "issue" regarding the cause of the homosexual disorder is an issue pushed by homosexual agenda advocates primarily as a 'reason' or 'justification' for the completely separate issue of sexual activity one participates in which is always a choice.

In other words --REGARDLESS if it is proven that there is a natural aberration in some to be born with a distinct hormonal impairment or whatever that predisposes some to engage in an activity that society rejects -Society will still reject the activity...

Such is termed a hypothesis -in the case of this subject article generally and in the case of a genetic cause specifically for the homosexual disorder - an unproven hypothesis

Well, sure. I thought that was the whole point of doing these studies on siblings and twins - to see if there is a genetic component to the chemical imbalance you described. It's unproven, certainly. But that's why they are doing research like this...

Do you have another hypothesis on what may cause the chemical imbalance side of the equation? I've seen lots of theories on the behavorial aspect, but very few on the chemical side of things.

Last time I tried to ask questions here I was punished by many lol....

It's happened to me too. There are those here who believe that merely asking a question is equivalent to taking one side or the other. And that sucks - nobody should be given a hard time for asking an honest question, regardless of who believes what. Incidentally, the question you asked earlier has occured to me too - my theory is that it would probably would make little difference in people's attitudes - this is one subject that people have a difficult time changing their personal defaults about - in either direction.

Thanks - I don't mind the hazing - I learn best when I have a question and ask it regardless of the return of exchanges.

Everyone has an opinion....which is good....what is also good is there are those who constantly seek to pick away at topics rather than accept the general line of pacification...

There are many aspects of sexuality which have been hidden, or changed over the evolution of man.... thinking here of the primate upright walking and the replacement (displacement) and size change of the sexual organs in both male and female to new positions to accommodate the new body design.

If there is a homosexual element in our development I would hope there will be enough curious humans over the future decades to get at the truth.

Nature herself has homosexuality activity in many animals - and while humans are not animals, and we do have the gift of decision-making and choice - I think nature wins the war over choice in some instances - and perhaps homosexuality is one choice which hasn't much of a chance. I don't know.

I figure questions are worth asking of learned members here, and don't mean to inflame people just want opinions - opinion is one of the few personal attributes we get to keep and nurture these days - we must guard them - but we must also be willing to look at what we perceive to be the "dark side" too on occasion, either to re-validate our own beliefs, or to update them.

Isn't is possible, however, that the chemical imbalance can have genetic causes?

Possible, but to me at least, not logical. Homosexuals, by definition, cannot reproduce, ergo a genetic predisposition cannot be passed along. Logically, the only way that it could be genetic is if it was an anomaly - the example that I used previously was 'Fragile-X'. Genetic anomalies are *very* rare in comparison to the incidence of homosexuality.

Unfortunately, my knowledge of both genetics and the endocrine system stops at High School anatomy.

Had an argument with a co-worker on this once...they thought that homosexuality was genetic and that societal pressures would influence gays to 'act straight'. Perhaps in today's society - but 30,000 years ago, did the same pressures exist? Possible, but I really don't think that it's likely.

Or, is homosexuality a relatively new (within the past 250 or so human generations) phenomenon?

Like I said before, the entire issue has become so politicized, that I doubt the answer will definitively be found, at least in my lifetime.

Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.