At the D11 conference on Wednesday, PayPal co-founder Max Levchin unveiled his new project: a quantification app for iOS that's aimed at helping women conceive. It's called Glow, and works primarily as a fertility and health tracker, gauging a woman's menstrual cycle and monitoring cervical mucus levels for indicators. Couples will be reminded to have sex at peak fertility times. Levchin estimates the reminders would arrive roughly every other day.