Nature vs. Nurture: The Biology of Sexuality
MED prof speaks tonight on whether sexual orientation has genetic basis
Homosexuality was considered a mental illness when Richard Pillard was in medical school. It was the 1950s and the School of Medicine professor of psychiatry was at the University of Rochester. At the time, the American Psychological Association still listed homosexuality as a disorder and psychologists and psychiatrists were trained on ways to treat it.
The first psychological test undertaken to determine whether there was a biological explanation for homosexuality was in 1957. With a grant from the National Institute of Mental Health, Karen Hooker studied the relationship between homosexuality and psychological development and illness. Hooker studied both homosexuals and heterosexuals—matched for age, intelligence, and education level. The subjects were then given three psychological tests: the Rorschach, the Thematic Apperception Test (TAT), and the Make-a-Picture-Story Test (MAPS). Hooker found no major differences in the answers given by the two groups. Because of the similar scores, she concluded that sexuality is not based on environmental factors.
In 1973, based on Hooker’s findings, the American Psychiatric Association removed homosexuality from its Diagnostic and Statistical Manual of Psychological Disorders and in 1975, released a public statement that homosexuality was not a mental disorder.
There have been numerous studies designed to determine whether or not homosexuality has a genetic cause. Among the most notable were a series of studies Pillard and J. Michael Bailey, a professor of psychology at Northwestern University, conducted in the early 1990s that found that homosexuality is largely biologically determined, not environmentally influenced. In their findings, published in the Archives of General Psychiatry, they argued that decades of psychiatric research into social and cultural causes show “small effect size and are causally ambiguous.”
Pillard and Bailey examined identical and fraternal twin brothers—as well as nonrelated brothers who had been adopted—in an effort to see if there was a genetic explanation for homosexuality. They found that if one identical twin was gay, 52 percent of the time the other was also; the figure was 22 percent for fraternal twins, and only 5 percent for nonrelated adopted brothers. Pillard and Bailey’s findings have been debated in the intervening decades.
Pillard is quick to point out that much about how sexual orientation is determined remains a mystery. “It’s really hard to come up with any definite statement about the situation,” he says. “I think some sort of genetic influence seems very likely, but beyond that, what really can we say? And the answer is: not a lot.”
BU Today caught up with Pillard to talk about the lecture he will deliver tonight, titled Born This Way: The Biology of Sexual Orientation. The talk is part of the OUTlook Lecture series, sponsored by the LGBTQ ministry at Marsh Chapel.
BU Today: Has your research found that sexual orientation is biologically determined?
Pillard: I think so. But nobody knows for sure what causes a person to be either gay or straight. It’s one of the great mysteries of science, at least of biological science.
Can you talk about the twin research you’ve conducted?
What we did was to recruit groups of twins, identical and fraternal twins. And the theory is if a particular trait is genetic, the identical twins would be more alike than the fraternal twins. The results were that they were more alike. The identical twins were far more similar than the fraternal twins.
Is there evidence that life experiences play a role in sexual orientation?
It’s a hard question to answer, because by “experience,” we’re talking about when kids are in the very first years of their life. If you’re going to do research about it, you’re doing research on people 20 or 30 years later, so it’s really hard to look back with certainty on what happened to them in those early years.
But a lot of people have tried, and have said things like, ‘Well, it depends on the fact that your mother was overprotective or that your father was distant or absent.’ You have to reconstruct those theories from events of long ago. And how do you know the mother really was overprotective—you have to depend on what the subject in your study is remembering about his early years. And that could be easily falsified.
Your research suggests that there is often a familial pattern in homosexuality.
Yes. It seems to us that being gay runs in families much more frequently than you would expect by chance alone. And the pattern is hard to specify: that is, in some cases they’re brothers and sisters, in some cases it’s parents and children, or aunts and uncles. So it’s hard to put that into theory given what we know about genes and behavior, which is to say, not a lot.
What made you decide on this research? What was your motivation?
Well, because there are so many gay people in my family, including me. It just seemed like a logical thing to do. At the time that I was searching for a problem, that popped out.
I think that the future of this kind of research belongs to people who are geneticists, people who are expert in gene mapping. These are the sort of bench scientists, where I am more interested in clinical things. I would be very interested if something came of this—that is, when the day comes where genes are mapped, I’d be very interested in that. But, it’s not something that I’m equipped to do.
Do you think that because attitudes are changing and acceptance of the LGBT community is becoming more prevalent, people are more willing to accept the possibility that sexual orientation is determined biologically?
It’s hard to say. Insofar as people look at evidence, it’s clearly biological. The objection to homosexuality comes exclusively from the conservative religious streak, who say, ‘Well, the Bible forbids it, therefore we must be guided by what the Bible says.’ But there’s no other evidence. Lesbians and gay men don’t do worse at their jobs, they are just as good as friends and citizens. As more gay people are out and open about their orientation, the general population realizes, ‘Well, they’re pretty much the same as everybody else.’
When I was in my medical school training in the 1950s, the only places you heard about gay people being were in prison or a mental hospital. So the assumption was, well they’re all quite bizarre. Then in the late 1960s, when civil rights were being granted to people of color and to women and finally to gays, it was realized that they’re like everybody else. I think most people now have friends or acquaintances who are gay. The average college student doesn’t think much about it.
Are you amazed at how far attitudes have changed?
Yes, but it’s taken a long time—50 years is a long time. But it absolutely is changing. Even so, there are people who think that gays shouldn’t be teachers or who are against gay marriage.
Since we don’t really know all the answers, people can have any opinion that crosses their mind. But I think most scientists, most people who are familiar with the science of the area, would say it’s very likely that something genetic is afoot here.
Will you be talking about sexual orientation in any kind of religious context?
I have to say I’m a hard-core atheist. I’m the last person who is qualified in any way to comment on theological matters. But I wonder what college students at BU think. Because I’m on the Medical Campus, I just don’t get the chance to rub shoulders with those on the Charles River Campus. It’ll be interesting to exchange views with them.
Because you’ll be presenting your evidence, and there’s no guesswork.
It’s just the facts, ma’am.
Richard Pillard will discuss Born This Way: The Biology of Sexual Orientation at 7 p.m. Tuesday, November 16, in Stone Science Building, 675 Commonwealth Ave., Room B50. Questions will follow the presentation. At 7 p.m. on November 18, Ellen Perrin, a Tufts University professor of pediatrics, will talk about Where Did We Go Right: Children Raised by Same Sex Couples, at the School of Education, 2 Silber Way, Room 130. Charles Morris, a Boston College professor of communications, will talk about Queer(ing) Public Memory: LGBTQ Pasts and Their Presence at 7 p.m. December 7, in SED 130. The events, sponsored by the LGBTQ Ministry of Marsh Chapel, are free and open to the public. For more information, contact Liz Douglass at email@example.com.
Kimberly Cornuelle can be reached at firstname.lastname@example.org Comments