I know that post wasn't addressed to me but I'd like to tell you how your response comes across to me.
As a white child (we're talking about as fair as a body can be), I had an aunt who married a black man. They had a child together. He turned out to be lighter than his father, but definately dark skinned. They lived 4 hours away in the big city and I rarely saw them except during the summers when my cousin would come stay for a week or so (ok...big holidays too). My grandmother on my Dad's side of the family would pitch a polite fit. "What will the neighbors say? Oh that poor child, what a predicament they have put him into....it just isn't fair to the child...blah, blah, blah." My cousin had a fine childhood and is now a high ranking officer in the Navy. He tells me that he wasn't picked on anymore than any other child. Sure...he got the name calling...mostly Oreo (black/white) but he maintains that other kids were singled out for other reasons as well...being fat, having pimples, being a jerk, teacher's pet and the list goes on and on as Mmario has pointed out previously. Your post has the same ring of "polite concern." Yeah, I can see your point but I don't think it's a big enough issue to not have same sex families be accepted as foster parents.
I have a friend who has 2 children with different fathers. Both men, after getting married to my friend and being Daddy for a few months, decided that they really couldn't live life as a straight man and both now actively live the life of a homosexual man. The children are 10 and 15 and all their friends know about their dads. They've been picked on some, but not like you would have it portrayed. I would also like to point out that teachers, bus drivers and other people who work with children are very quick to squash that kind of teasing...just as they are with the racist remarks. Yes, I know, kids aren't supervised 100% of the time and some hurtful things will be said...but honestly, if it weren't that, kids would find something else to tease about.
So, yeah...the "polite concern" comes off as covered up bigotry from someone who is trying to save face.
Sorry dude...not trying to be rude...but you asked and I'm doing my best to explain.