As with the Christian who argues that we only behave morally under threat of a punishing God, “Yo Mama Was Pro-Life” is another common argument (or bumper sticker) that I find self-defeating. It is conventionally used to suggest that the listener – especially the pro-choice listener – should be grateful that his/her mother was pro-life. But all it really does is remove the grounds for gratitude. “Your mama was pro-life” suggests that she carried you to term not because she wanted you but because she was obligated by an external religious injunction. “Your mama was pro-choice,” on the other hand, implies that she carried you to term not because of external mandates but because she truly wanted you.
So if you want someone to feel warm and fuzzy about your pro-life agenda, please don’t tell them that their mama was pro-life. First of all, it makes you look silly – as if you believe in some inane “logic” that says a woman cannot have a baby and be politically pro-choice. And secondly, it insults the very listener you are trying to win over by suggesting that his/her mother carried them to term only grudgingly, only out of an enforced obligation.