Not saying that it "hurts everyone", but the institution of marriage is in trouble as it is.

It is not the fact of the marriage; it is the fact of the message that is being sent to children. Many are being exploited with this new attitude. A lot of problems can and do revolve around emotional, social, and psychological well-being as a child is developing their sexual identity. I think it's really confusing to be taught that homosexuality is "normal". I also think other children's peers are a factor that have not been considered enough. Children can be very cruel to each other.

Simply put, children learn what they see.