My little sister was once a pro-choice, vegan animal-rights activist. She believed we shouldn’t kill bees for their honey. To try to convince her that a fetus was a life as worthy of protection as a honeybee, I used the magical vaginal fairy dust argument on her.

It goes like this: The vaginal canal is only a few inches long — is there magical fairy dust that is sprinkled on a fetus as it passes through the birth canal that confers humanity? A few inches higher, before the fairy dust, killing okay. A few inches lower, after fairy dust, killing not okay. Magical!