Last Sunday’s homily included railing against same-sex marriage (oh goodie!) using the good old reproduction argument. The priest’s exact words went something like this: “Only a man and a woman can join together to create life. The proper way to create life is within marriage. A man and a man cannot create life! A woman and a woman cannot create life! It is impossible! Ask any scientist, and he will tell you this is true!”

Well, maybe you shouldn’t ask any scientist. In particular, don’t ask the Japanese scientists who created a genetically unique offspring by combining the genes of two female mice. This may never be attempted using human genes, but we can no longer say with complete accuracy that same-sex reproduction is “impossible.”

Of course, this “success” happened in a laboratory after many failed attempts, so one could certainly argue (rightly so) that such a thing is not “natural.” But we get into murky territory when we start using that argument against homosexuality, too. Because scientific research also shows that homosexuality is, in fact, natural. And while same-sex reproduction may not be “natural,” many anthropologists feel that the rearing of children by same-sex parents serves a biological function: namely, that there are “extra” parents around who are not diverting resources by having their own children but are still contributing to the well-being of a society’s next generation. This, they argue, is why homosexuality has not been eliminated from the gene pool — it serves an evolutionary function. And, oh dear, it’s OK for Catholicism to accept the scientific evidence of evolution. Do you see how quickly this issue gets sticky?

Look, where I fall on this issue has never been a big secret. I believe that homophobia, not homosexuality, is the true “sin” that plagues organized religion. When I write fiction with gay themes, a writer friend of mine whose Christianity leads her to believe differently than I do about this issue, often asks, “Are you trying to argue for the ‘rightness’ of homosexuality?”

And I say, “No. I’m trying to argue against the ‘wrongness’ of homophobia.”

And just so now, I’m not trying to argue for the “rightness” of same-sex reproduction, or the “rightness” of homosexuality in nature. I’m arguing against the “wrongness” of basing arguments against homosexuality on science when the science doesn’t actually back you up. If you want to use religion to justify your prejudices, that’s your own prerogative (just as it is mine to disagree with you.) But we need to be very careful when trying to twist science to support our prejudices. Because science is not easily twistable. Evidence is so inconvenient, isn’t it?