So far as I can see, far worse harm is done to children who are born of parents who, for whatever reason, don't want them, rather than of parents who very much do want them.
No doubt there's a risk of harm, but there's no reason, as yet, to believe that it's an increased risk, to raise children in a typical family of same-sex parents as opposed to an average heterosexual family. I agree that when you hear cases about parents aggressively raising their child to be gender-neutral, you wonder how much it's about the parents' wishes rather than the child's... but those cases are rare, and in any case, it can be equally dangerous if not more so to interfere from outside.