A kid raised by a Homossexual couple will be directly induced to be gay, not to mention the ammount of bully they will suffer.
I am not gay, but recently turned out that my father is. After all these years he tried hiding it and believing he was not. He never chose it. He's been hiding it on the last 48 years (his age at the moment).
Animals can be homossexual too, it's scientifically proved. Why not humans then? It's been out for thousands of years, and we've been accepting it until then. It's not about us to have such a hate for it. The Church has been changing people's mind about homossexuals, as they consider it a sin. And most of the ones who believe in it, take it VERY seriously. In fact, the first homophobics (the ones that kills/hurt gay people) we're priests.
About adoption, I haven't seen my father since then, but i heard that he and his "partner" adopted a little boy (around 3 or 4 years old), I feel bad for him, not because he will be raised by 2 gays, but because he will suffer a lot, bullying is still out there. And by now, i can consider him as a brother that i might never see.
Overall: gays are out there and we have to face it, sometimes they hide it because they know how society doesn't accept them. And that's why we should.