No matter if ppls are normal or not Islam doesn't allow adoption to save child who knows what is the purpose of adoption.
Islam does allow to adopt lesser of an evil to save someone from a bigger evil. Alcohol is allowed if that is the only choice of medicine left, eating pig is allowed if person is literally dying of hunger..
What I said about gay adoption is just in comparison. I was not justifying that. Just saying that if we are left with choice between 2 evils, Islam does permit to adopt the lesser evil.