So if a boy has several older brothers, and is right handed, does that
make him more likely to live a life considered sinful by the church?
The Science Of Sexual Orientation
March 12, 2006
(CBS) There are few issues as hotly contested =97 and as poorly
understood =97 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
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.
Adam wears pinkish-purple nail polish, adorned with stars and diamonds.
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
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.
Bailey says he doesn't think nurture is a plausible explanation.
Psychologists used to believe homosexuality was caused by nurture =97
namely overbearing mothers and distant fathers =97 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
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.
"Yeah, absolutely," he replied.
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,"
"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=85both 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 =97 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
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
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 =97 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.'"
"I wasn't ready just yet," Greg added.
Does this prove that it's not genetic?
"What it proves is it's not completely genetic. They have the same
genes," says Bailey.
Asked if that brings us back to the mother and the father, Bailey says no.
"But that's environment," Stahl said.
"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
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
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.
But a male rat did. He was castrated at birth, depriving him of testostero=
"So you created a gay rat?" Stahl asked.
"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
So the answer may be that it's not genes but hormones.
"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
"The more older brothers a man has, the greater that man's chance of
being gay," says Bailey.
Asked if that's true, Bailey says, "That is absolutely true."
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."
"You mean, like she's carrying a foreign substance?" Stahl asked.
"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.
It's still not a proven theory and it gets even stranger.
"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?
Adam and Jared, fraternal twins, have older brothers, but they're
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 =97 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.
Asked if he wished he was a girl, Adam nodded.
"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.
"Yup," Adam replied.
By Shari Finkelstein (c)MMVI, CBS Broadcasting Inc. All Rights Reserved.