The adoption one just doesn't work at all, because the moral objection to fathering a child is that there are too many children who need homes already, so adopting in that case is helping solve the problem, not taking advantage of someone else's willingness to get their hands dirty.

Do you know how many cows and chickens there are in the world? What would we do with them all if we didn’t kill them for food (or leather or feathers, etc.)? By eating them, you’re helping solve the problem....