I just want to know more before I can decide if gays should be allowed to adopt kids.
You are waaaay too late. Gays, both single and couples are already adopting kids, and have been for years, mostly kids deemed as otherwise unadoptable. So you are willing to consign these children to a life of serial foster care, bouncing from one home to another, rather than a loving home headed by one or two people who happen to be gay? So you thing the gay parent is a worse choice than foster care because of the possibility of the child growing up to be gay? That makes absolutely no sense. Not to mention, gay couples have been having biological children, in one manner or another forever.