Dr John Willke: Obstetrician who retired in order to campaign against abortion and said that few rapes result in pregnancy

Other doctors, and abortion rights advocates, accused Willke of ignoring the facts and science

John Willke was an obstetrician who helped shape the modern American anti-abortion movement with ideas that including a belief that a woman can resist conception from a sexual assault. He stopped delivering babies in the late 1960s to oppose abortion, retiring from his medical practice in 1988 to devote his life to the anti-abortion movement. He participated in protests and congressional hearings and frequently appeared on national television.

Other doctors, and abortion rights advocates, accused Willke of ignoring the facts and science, particularly in his view on rape and pregnancy. Congressman Todd Aikin drew criticism from fellow Republicans and lost his 2012 Senate bid after making comments that reflected Willke's view.

"There's no greater emotional trauma that can be experienced by a woman than an assault rape," Willke had written in 1999 in the journal Christian Life Resources. "This can radically upset her possibility of ovulation, fertilisation, implantation and even nurturing of a pregnancy." He claimed that sexual assaults resulted in only about four pregnancies per state per year. A study published in 1996 by the Medical University of South Carolina estimated that there are in fact approximately 32,000 pregnancies resulting from rape in the US each year.

In 2012 the American Congress of Obstetricians and Gynaecologists said a woman who is raped "has no control over ovulation, fertilisation or implantation of a fertilised egg", and that to "suggest otherwise contradicts basic biological truths." Michael Greene, a Harvard professor of obstetrics, gynaecology, and reproductive health, was more direct: "There are no words for this," he said. "It is just nuts."

When the Akin controversy broke, Willke weighed in, saying, "This is a traumatic thing – she's, shall we say, she's uptight. She is frightened, tight, and so on. And sperm, if deposited in her vagina, are less likely to be able to fertilise. The tubes are spastic."

But those words didn't damage his standing with Republicans: Mitt Romney's 2008 run for president embraced Willke as, according to a campaign spokesman, "an important surrogate for Governor Romney's pro-life and pro-family agenda". Romney expressed his pride to "have the support of a man who has meant so much to the pro-life movement in our country."

In 1971 Willke and his wife, Barbara, co-wrote the Handbook on Abortion, which sold 1.5 million copies at the height of the sexual revolution and has been reprinted many times and in many languages, influencing generations of anti-abortion activists. Barbara, who died in 2013, said in 1999 that the couple didn't originally plan to get involved with abortion until questions from their daughters and friends caused them to take a closer look at the issue.

LISA CORNWELL

John Charles Willke, author and activist: born Maria Stein, Ohio 5 April 1925; married Barbara (died 2013; six children); died Cincinnati, Ohio 20 February 2015.