As a younger man, he had been strongly
pro-choice, and he claims that he performed an
abortion on a woman who had become pregnant by him.
[1] 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 over 75,000 abortions throughout his pro-choice career.
The development of ultrasound, however, in the
1970s led him to reconsider his views on abortion. He is now a staunch supporter of the pro-life movement. In
1984, he made the documentary
The Silent Scream which showed an abortion from the perspective of
ultrasound. His second documentary
Eclipse of Reason dealt with
late-term abortions. He has also stated that the numbers he once cited for NARAL concerning the number of deaths linked to illegal abortions were "false figures".