- Studies point to biological factors, but research is ongoing.
- Recent research backs up Alfred Kinsey's work from the 1940s showing a continuum of sexuality.
- Actor Cynthia Nixon recently stirred controversy when she declared that she had chosen to be gay.
Actor Cynthia Nixon recently stirred controversy when she declared that she had chosen to be gay.
The quote that prompted the debate? It appeared in a profile of Nixon in the New York Times Sunday Magazine:.
"I gave a speech recently, an empowerment speech to a gay audience, and it included the line 'I've been straight and I've been gay, and gay is better.' And they tried to get me to change it, because they said it implies that homosexuality can be a choice. And for me, it is a choice. I understand that for many people it's not, but for me it's a choice, and you don't get to define my gayness for me. A certain section of our community is very concerned that it not be seen as a choice, because if it's a choice, then we could opt out. I say it doesn't matter if we flew here or we swam here, it matters that we are here and we are one group and let us stop trying to make a litmus test for who is considered gay and who is not."
In the aftermath of Nixon's take on her sexuality, a discussion about the origins of homosexuality has been reignited. The Sex in the City star raised questions about the idea of sexual fluidity and prompted some to ask questions about how we think of sexual orientation.
Many scientists, though, have concluded that sexuality is at least partly determined by biology.
"Biology tells us that sexual orientation is strongly influenced by prenatal hormonal and genetic factors and there is little information supporting the notion that education or interactions with peers play any substantial role," said Jacques Balthazart of the University of Liege in Belgium, and author of The Biology of Homosexuality. "This being said, the part of the variance explained by biology is still limited and there is possibly room for personal choice. In addition, multiple factors probably contribute to determine homo versus heterosexuality and this could vary from one individual to another."
One landmark series of studies on twins in the early 1990s, for example, showed that if one identical twin is gay, the other has a 50 percent chance of also being homosexual. Psychologist Michael Bailey of Northwestern University's work showed that among fraternal twins (who do not share the same DNA), the probability drops to 20 percent.
Other studies have noted specific detailed differences between people with different sexual orientations: for example, a 2011 study published in Frontiers in Neuroendocrinology showed that oto-acoustic emissions in the inner ear are more frequent in women -- unless the woman is lesbian. In animals treated with androgenic hormones as embryos, the emissions also lessen, leading researchers to believe that prenatal hormones play some role in sexual identity.