In 1996, a particularly devastating nail was driven into the coffin of “homosexuality is a choice” rhetoric. A team of researchers found that the more older brothers a boy has, the greater the likelihood that he will grow up to be gay. Since the research was first published in the American Journal of Psychiatry, many other scientists have replicated the fraternal birth-order (FBO) effect on male sexual orientation. One promising hypothesis to explain this phenomenon is “maternal immunization”; that is, that after delivering several sons, a woman’s body begins to produce antibodies that affect male-specific proteins. This reasoning is consistent with two important features of the FBO effect: first, the effect is not observed in daughters with older siblings of either sex. Second, it is only observed in sons with the same mother, but it seems to make no difference whether or not the male children have different fathers. Even when brothers of the same birth mother are raised in different homes, the effect is observable, suggesting that uterine environment, not home environment, is the important factor.
All things considered, about half of male homosexuality is a result of the FBO effect. Other biological factors–genetic, epigenetic, and hormonal–appear to affect sexual orientation in most of the other half of cases. Lesbianism, in general, seems a tougher nut to crack, and some researchers hypothesize that female sexuality may be simply more “fluid.” That said, fetal testosterone exposure is one promising line of investigation that explains at least some instances of female homosexuality.
In the wake of so much research, how could any thinking person, even any thinking religious person, not start to doubt the “lifestyle” axiom? At the very least, these pesky scientific findings obliterate the first iteration of “it’s a choice”–that God created humans with the correct generative impulses such that any deviation must, by definition, be a conscious decision to engage in hedonistic perversion. This said, recent scientific findings might have given extra steam to the more sinister version of “it’s a choice”: ever the trickster, God sprinkled a little fairy dust–pun intended–on just a few unwilling souls as a means to test their allegiance. (The Christian concept of free will, which believers sell as a liberating force, has nonetheless cast God in the role of abusive spouse. It’s our fault that he hits us because we burned the toast.)
Still, secularists have something to celebrate when “it’s a choice” starts to crumble and crack. But we also have something to be wary of. In response to recent sexual-orientation research, some Christians have pointed out that another nonstandard sexual drive–pedophilia–also may be biologically determined. So the logic goes: “If research on pedophilia suggests genetic, congenital, or other innate causes for sexual attraction to children, then society will grant free passage to child abusers, just as it has to homosexuals. Thus ‘it’s not a choice’ is a slippery slope.”
Obviously, once the line of reasoning waddles in this direction, we freethinkers have a ready no-brainer of an answer: what differentiates the homosexual from the pedophile is the fact that the former has sex with consenting adults. The latter, on the other hand, takes victims. But this no-brainer has become a secondary rather than a primary defense of homosexuality. In other words, when religious people make the slippery-slope point, they’re showing us the greatest flaw in secularism’s campaign to normalize homosexuality and encourage tolerance: the dominant message that homosexuality is a-ok precisely because it’s not a choice. Since when do secularists elevate biological destiny over, well, choice–the very word we use to campaign for reproductive rights? And if gay people can marry only because the biological lottery has bestowed upon them a same-sex preference, why not require an FBO-certification test to prove that Bruce and Paul’s nuptial vows are about more than just Social Security benefits? For that matter, if Bruce wants to marry his best gal-pal Paula, why not require that he first undergo a vagina-appreciation genotyping assay?
Secular acceptance of homosexuality is not–nor has it ever been–answerable to scientific research. The scientific roots of sexual orientation and drive–however interesting and worth pursuing–are beside the point when the issue is political. Homosexual people are due equal rights to marry and otherwise participate in society, not because they “can’t help it” but because they are citizens who pose no threat whatsoever to their neighbors. End of political argument. No one needs a permission slip from religion to live one’s life. But no one needs a permission slip from science, either.
Katrina Voss worked for ten years as a bilingual meteorologist at Weather Channel Latin America and AccuWeather. She is now a science and research writer at Penn State’s Eberly College of Science.