Have you ever met anyone who has had a sex change?
The person carrying the child is a biological woman, who has chosen to want to live as a man. S/he is entitled to have a child if s/he wants to.
The child will have a mother and a father, and it is wanted and will be loved. On another thread there is a discussion about a family whose child went missing and is now the subject of what could very well include child sex abuse.
If I were a child, I know which family I would prefer to be born into.