well this is the best i can find....i looked through a couple of books about attachment and this is all I could come up with....

Attachment Disorder -- a mental and emotional condition occurring during the first three years of life where a child does not attach, bond, or trust his or her mother.

The importance of an attachment relationship between mother and child cannot be over-emphasized. Attachment is all about building relationships. Humans need attachments with others for their psychological and emotional development as well as for their survival. Infants need to be physically close to the mother and be able to receive and give affection to form an enduring emotional bond.

So being put in foster care alone can cause problems.....HOWEVER

I recently read a study about attachment and it is possible for a child to lead a perfectly happy life after it has been in adoption.....but only if it is taken by new parents and not it's biological parents...

so I believe (apart from bullying) that it is possible for the child to have a "normal" happy childhood with loving gay parents...

Polymirize that is a very good point...althoguh i don't completly understand all of what you are saying.....