In genetic defense of gayness

Some talk in Gov today got me thinking about homosexuality in all its controversial glory. Most evidence points to an unusually feminine (or masculine) physiology as the prime cause of homosexuality. This itself is caused primarily by prenatal factors. So, do we label homosexuality a disorder, as with other mental anomalies? Where is the line drawn between a disorderly mind and "normal" mind? Where is the line drawn between disorderly behavior and "normal" behavior? Homosexuality tends to be detrimental to reproductive success (for obvious reasons), so I can't forsee any sympathy from the genetically-minded crowd. Then again, the specific definition and classification of normal vs. abnormal is far more than I hoped to touch on in this post.

Homosexuality has been a sort of proverbial thorn in the side of evolution, especially Dawkins' brand. Sociobiologists have attempted to write homosexuality off by ascribing its existence to its benefits in situations of overpopulation. This view has been largely discredited. From every evolutionary perspective, homosexuality should have gone extinct long ago. This is especially true for the selfish gene theory, as it amounts essentially to sterility (= genetic death = no survival).

There's a pretty simple and obvious answer to that whole "problem", which is not really a problem at all. Homosexuality is not hereditary (duh). There is no "gay" gene, and if there were, there still wouldn't be for reasons already mentioned. So then all homosexuality must arise from environmental factors, be them prenatal or postnatal. This puts it much further out of the range of the gene than panderers of the above reasoning would like to understand. The closest to genetics that homosexuality could get, then, would be the protoeme of the womb when it occasionally spits out a destined flamer. It's obvious that a highly efficient womb system which screws up only about 7% of the time with a gay/sterile child probably won't be selected against, especially when there's no small alteration that would yield a surefire successful system. Thus, there's really no reason why homosexuality can't exist and no reason why its existence should be irreconcilable with evolution as we know it.
This whole concept doesn't seem to be as obvious in the scientific community as it probably should be.