Kuya, did you actually link to Concerned Women for America as a legitimate source? (An an online Mormon journal?) Read Mustanski's paper that the Concerned Bitches cite. The authors clearly acknowledge the limitations of the study, and even if it doesn't support a genetic basis for homosexuality based on the genes investigated, it certainly doesn't refute a genetic basis, either.
LeVay's 1991 paper is also problematic. He looked at brains of gay men who had died of AIDS, which presents two problems: the disease may have altered the relevant areas of the brain so they'd be different from healthy men and women, and that particular part of the brain could (then, I don't know about now) be observed in autopsy and not while the subject was alive so death itself may have affected the brain. I believe even he addresses this in
Queer Science.
In any case, no serious person argues that sexuality is a purely genetic trait, and especially not the result of a single gene. That doesn't mean it doesn't have a biological basis, though. The fetal environment can affect development, and there's a hypothesis that fraternal birth order could be responsible in some situations:
ScienceDirect - Journal of Theoretical Biology : H-Y Antigen and Homosexuality in Men