Sex for Procreation

Morality Teacher: The church recognizes that sexuality is something you are born with, but the reason that gay sex is immoral is because sex is supposed to always to be open for procreation.
Me: But what about if a woman is born infertile, is it just crap luck and she can't ever have sex either?
Morality Teacher: That's a little different, as long as she's open with becoming pregnant then it would be open to procreation and therefore moral.
Me: What if a gay guy was totally okay and open to getting pregnant? It's just as likely and the exact same thing.
Morality Teacher: ....I don't know man