Silent Scream

As a younger man, he had been strongly pro-choice, and he states that he performed an abortion on a woman who had become pregnant by him. He later gained national attention by then becoming one of the founding members of the National Association for the Repeal of Abortion Laws, now known as NARAL Pro-Choice America. He worked with Betty Friedan and others for the legalization of abortion in the United States. Their efforts essentially succeeded with the Roe v Wade decision. He was also for a time the director of the Center for Reproductive and Sexual Health (CRASH), New York's largest abortion clinic. Nathanson has written that he was responsible for more than 75,000 abortions throughout his pro-choice career.

The development of ultrasound, however, in the 1970s led him to reconsider his views on abortion.