My friends are having a debate about whether the rhythm method will work as birth control for Romy.

Romy is having a whole bunch of sex with a relatively new boyfriend. She already got pregnant (and aborted) once due to misreading an ovulation test strip. She feels confident that she won't get pregnant again by using the rhythm method. She's not on birth control and they don't use condoms.

Aaron is suspicious and thinks she's seriously risking another pregnancy. They're debating so I told them I'm making a prediction market.

If Romy intentionally gets pregnant, this will resolve to no (but she reports definitely not wanting to have a baby before February)