In the past few weeks, most people have probably seen Britney Spears' name or face everywhere. When she stood in front of a judge (virtually) and protested the conservatorship she's been living under for the past 13 years, one harrowing detail in particular stood out. She told the judge, "I was told right now in the conservatorship, I'm not able to get married or have a baby." Today, we look back at an old episode where we explore why it is that hundreds of thousands of people can have their reproductive rights denied...and spoiler: it goes back to Darwin. When a law student named Mark Bold came across a Supreme Court decision from the 1920s that allowed for the forced sterilization of people deemed “unfit,” he was shocked to discover that it had never been overturned. His law professors told him the case, Buck v Bell, was nothing to worry about, that the ruling was in a kind of legal limbo and could never be used against people. But he didn’t buy it. In this episode we follow Mark on a journey to one of the darkest consequences of humanity’s attempts to measure the human mind and put people in boxes, following him through history, science fiction and a version of eugenics that’s still very much alive today, and watch as he crusades to restore a dash of moral order to the universe. This episode was produced by Matt Kielty, Lulu Miller and Pat Walters.  Special thanks to Sara Luterman, Lynn Rainville, Alex Minna Stern, Steve Silberman and Lydia X.Z. Brown. Radiolab’s “G” is supported in part by Science Sandbox, a Simons Foundation initiative dedicated to engaging everyone with the process of science. Support Radiolab today at Radiolab.org/donate.