The writer in Don's link recent link #4 is definitely writing from a conservative Christian perspective. He clearly states his own "understanding that the cause of homosexuality is a highly complex combination of various factors, some genetic and some environmental". This is from someone conservative enough to cite Timothy LeHaye, an extremely onservative Christian, for support.
As to LeHaye, some of the environmental factors he lists would seem credible; a couple of others would be laughable if they weren't sad: "Youthful masturbator and fantasizer"; it's a wonder males aren't at least 98% gay. "Permissive childhood training", which could mean anything from not ruling with an iron hand to truly inadequate parenting, instilling no values or self-discipline; I would wager that that would in fact correlate with a tendency to promiscuity, but why would it determine what gender the developing child is attracted to?