You can say he should behave differently, but what happens when he realizes the child isn't going to change?
And "support" can come in a variety of ways. It doesn't have to mean complete approval and endorsement.
There have been a lot of homosexuals in the royal family and even more working for them, and presumably that won't change any time soon.
Much of that was going on when the Church of England condemned homosexuality. Having homosexuals in the royal family or the monarch's court didn't constitute an endorsement of homosexual activity.
The only one we're sure is not a queen is...the Queen!