"I'll marry you, but I don't want to be a woman", Sam protests."
Before you can answer, he continues: "But since you don't either, and your dad is a jerk, how about we decide it via a contest."
"What do you propose?", you ask. "Anything physical and you clearly have the advantage, you're much more fit. And my grades are miles ahead of yours, so I have the advantage in anything intellectual. What would even be a fair contest for the two of us?"
"That's easy." Sam replies. "Whichever one of us becomes a woman first loses."
"Huh?"
"Were you even paying attention in health class? A man who gets impregnated doesn't immediately become a woman, they transition slowly over the course of 12-24 hours. And if you take emergency hormone blockers, you can block the embryo from implanting which will cause the changes to reverse. So what I propose is that we both come inside each other, and whoever finishes transforming first will become the woman. The winner takes the emergency hormone blockers and reverts back to being a man."
After pondering Sam's offer, you decide...