Who should be prevented from having children? And who gets to decide? Across 20th century America, there was a battle to control birth - a battle which rages on to this day.

In 1907, the state of Indiana passed the first sterilisation law in the world. Government-run institutions were granted the power to sterilise those deemed degenerate - often against their will.

In the same period, women are becoming more educated, empowered and sexually liberated. In the Roaring Twenties, the flappers start dancing the Charleston and women win the right to vote.

But contraception is still illegal and utterly taboo. The pioneering campaigner Margaret Sanger, begins her decades long activism to secure women access to birth control - the only way, she argues, women can be truly free.

In the final part of the episode, sterilisation survivor and campaigner Elaine Riddick shares her painful but remarkable story.

Contributors: Professor Alexandra Minna Stern from the UCLA Institue of Society and Genetics, Professor Wendy Kline from Purdue Univerity, Elaine and Tony Riddick from the Rebecca Project for Justice

Featuring the voice of Joanna Monro

(Photo: Elaine Riddick was sterilised without her consent, when she was 14, in North Carolina. Credit: Tami Chappell/The Washington Post/Getty Images)