Latest research on sexual preferences

The San Jose newspaper reported today:

Growing research suggests being gay is not 'a choice'

Compared with straight men, gay men are more likely to be left-handed, to be the younger siblings of older brothers, and to have hair that whorls in a counterclockwise direction.

Researchers are finding common biological traits among gay men, feeding a growing consensus that sexual orientation is an inborn combination of genetic and environmental factors that largely decide a person's sexual attractions before they are born.

Such findings — including a highly anticipated study this winter — would further inform the debate over whether homosexuality is innate or a choice, an undercurrent of the recent Proposition 8 campaign in which television commercials warned that "schools would begin teaching second-graders that boys could marry boys," suggesting homosexuality would then spread. ...

"In the past decade, I think the pendulum has swung more toward biological theory and biological causes," said Richard Lippa, a psychology professor at California State University-Fullerton, who has studied hair patterns and other biological traits in gay men."

Here is Prof. Lippa' research:

In a new study published in the Archives of Sexual Behavior, Canadian psychologist Ray Blanchard and California psychologist Richard Lippa extended recent research on handedness, birth order, and sexual orientation by analyzing data from over 200,000 men and women who completed a survey posted on the BBC Science and Nature website. Survey participants reported their sexual orientation, their degree of right- versus left-handedness, and how many older brothers and sisters they had.

Some of the major findings of the new study:
* More gay men than heterosexual men reported being left-handed (13% versus 11%).

This is unconvincing. There is no proof that left-handedness is genetic, or even inborn. Even if it were, the correlation with homosexuality is slight, and not necessarily inborn. Professional baseball players might be 30% left-handed, but that would not show that being a baseball player is not a choice.

It is possible that there is a gene for right-handedness, and those without the gene are equally likely to be right or left handed. About 3% of men are homosexual, according to some surveys. If so, then maybe 3.5% of left-handed men are homosexual, and 2.9% of right-handed men are. That would be consistent with the about study. But that says nothing about whether being gay is a choice, or whether being gay is inborn.

There is no scientific proof that being gay is inborn, and no evidence that being gay is any more likely to be inborn than a lot of other human behaviors. Nearly all such behaviors are a subtle combination of nature and nurture. The details are not well understood.

Even if it were proved that homosexuality were inborn and not a choice, that would not necessarily have any bearing on political opinions about whether same-sex marriage should be taught in the schools. The anti-P8 campaign dishonestly claims that same-sex marriage would not be taught, or that parents could opt out. It is already being taught in the public schools in my district. My guess is that the schools are also teaching that scientific evidence shows that homosexuality is not a choice. The newspapers print such propaganda, but it is just not true.