It’s not even a close call. Gay men are, how to put this with sufficient sensitivity so it doesn’t appear as though a gay man is somehow incomplete. Let’s start with a definition of gay: “of, pertaining to, or exhibiting sexual desire or behavior directed toward a person or persons of one’s own sex;” A father is not capable of “exhibiting sexual desire” towards an man. Fathers desire women. Gay men desire men. The difference in their Sexual Desire or Sexual Attraction is the essential difference in the nature of gay and straight men, the essential attribute of a father.
Gay men and Lesbian woman can certainly attempt in good faith to be a father to a child, father not in the Sexual Attraction sense but in the “caretaker” sense but even the best gay or lesbian cannot be a natural father given the nature of a gay man or a lesbian woman.
The purposeful blurring of the lines between fathers and gay men by claiming, wrongly, that gay men can be loving and caring and on occasion more loving than a father is nothing more than the seeds of the destruction of marriage. No matter how hard the spin, the essential attribute of a father is unachievable to a gay man. fathers love mothers. Gay men love other gay men. Gay men are neither fathers or mothers nor can they be.
Gay men can never be fathers. Sure, in vitro and sperm freezing aside, if a man is gay he cannot be a father even though sperm can be harvested. A gay man can help a mother raise her child or any other children he is inclined to support. Fine, but that’s like playing a part compared to living the part.