Today, home pregnancy testing is completely taken for granted. It is implicated in personal decisions and public discourses around all aspects of reproduction, from miscarriage and abortion to the biological clock and IVF. And yet, only three generations ago, women typically waited not minutes, but months to find out whether they were pregnant. In this presentation I will recover the contested rise of a little-studied technology, from around 1900 to the present day. I will show how the demand for pregnancy testing decisively shifted from doctors to women, first as patients and then as consumers, and work through the core argument of my book-in-progress, which seeks to explain the remarkable transformation of pregnancy testing from a taboo diagnostic service to a commonplace of everyday life.