When my friends Joe and Patty Muñoz started family planning two years ago, they found several mobile apps to help them monitor ovulation and basal body temperature. The apps tended to be loaded with questionable functionality and visual clutter. Joe is a mobile developer himself, and he and Patty enlisted me to design the user interface for a simpler fertility tracking app. We omitted the cruft and designed an application that does just a few things well. Lity for iOS and Android was released in December of 2015.