When children end up in families they are partly or completely unrelated to this invariably seems to end in these parents and children somehow existentially pitted against each other.
The children have at least part of their identity concealed or unacceptable or, at best, neglected and unknown. Even the most benevolent adoptive parents cannot, say, help their adopted kids develop parts of themselves that derive from their genetic heritage.
The children's feelings of loss are not allowed and they are expected to conform to the family as defined by the parents. I see this as potentially problematic in direct proportion to the number of genetically unrelated persons that the child has to refer to as "parents" in that child's life.
On the other side are the parents. They really want to create their perfect family. They really believe they can use other people's children as materials. When those children beg to differ - even other DC adults or adoptees on the Internet - the very essence of all their hopes and dreams seems to be shaken.
This shows there's something fundamentally wrong about selling the idea that you can solve your infertility issues and create your very own perfect family out of other people's kids. You can't.
I'm not necessarily against adoption or even donor insemination in all cases. But I definitely don't believe they should be allowed to keep being touted as ways for infertile couples to become parents. Infertile couples can take care of other people's kids through adoption - and how about trying to restrict this to genuine orphans? But they should not be guaranteed the right to claim these children as their own and it is up to the children to be allowed to define their families according to their own criteria.