Dr. Willke, shown here in 1995 at an anti-euthanasia conference in Amsterdam, died Feb. 20 at 89. (Peter Dejong/AP)

John C. Willke, an Ohio physician who helped lead the movement to outlaw abortion in the United States, supplying fellow advocates with arguments that included a widely rebuked claim about a rape victim’s ability to conceive, died Feb. 20 in Cincinnati. He was 89.

A daughter, Marie Meyers, confirmed his death and said she did not know the cause.

A son and grandson of physicians, Dr. Willke was a general practitioner who delivered babies, among other services, before turning to advocacy work in the late 1960s. He helped found antiabortion organizations in Ohio before advancing to the national stage, where he served as president of the National Right to Life Committee for a decade before retiring in 1991.

Dr. Willke often wrote and spoke in tandem with his wife, Barbara, who was a nurse. Together they became prominent figures in the community of abortion opponents that was galvanized by the 1973 U.S. Supreme Court ruling in Roe v. Wade that effectively legalized the practice nationwide.

A 1971 primer written by the Willkes, “Handbook on Abortion,” sold 1.5 million copies, according to the Associated Press, and was perhaps the most widely circulated text among antiabortion advocates. “No single English-language volume has serviced the antiabortion movement quite like Jack and Barbara Willke’s book,” The Washington Post reported in 1990.

The handbook — which was translated into other languages — laid out the essential belief, held by Dr. Willke and his supporters, that life begins at conception and that abortion is therefore tantamount to killing.

“This is a unique being, containing within itself a genetic package, completely programmed for and actively moving toward adult human existence,” the Willkes wrote. “It has, by any standard, a life of its own and in no way is part of the mother or father.”

The Willkes also prepared slide shows containing images of aborted fetuses, their infant features clearly identifiable. Those images were to be presented to audiences in an effort to convince them that the womb contained a human being. Dr. Willke appeared frequently on the radio and television.

In a debate marked by high emotions on both sides, abortion rights supporters contended that Dr. Willke’s positions barred women from maintaining control over their bodies. Some fellow abortion opponents criticized him because he allowed for exceptions in abortion laws for cases of rape and incest.

Dr. Willke was most roundly criticized for his stance on pregnancy resulting from rape.

“There’s no greater emotional trauma that can be experienced by a woman than an assault rape,” he wrote in a 1999 article. “This can radically upset her possibility of ovulation, fertilization, implantation and even nurturing of a pregnancy.”

The position was subjected to wide scrutiny in 2012, when Todd Akin, a Republican congressman from Missouri then running for the U.S. Senate, was asked in an interview to explain his opposition to abortion, including in instances of rape.

“If it’s a legitimate rape,” he said in comments that provoked near-universal condemnation, “the female body has ways to try to shut that whole thing down.”

In reaction to Akin’s comments, Dr. Willke was asked to explain how the experience of rape might impede conception.

“This is a traumatic thing — she’s, shall we say, she’s uptight,” he told the New York Times. “She is frightened, tight and so on. And sperm, if deposited in her vagina, are less likely to be able to fertilize. The tubes are spastic.”

At the time of the controversy, the American Congress of Obstetricians and Gynecologists declared that a rape victim “has no control over ovulation, fertilization or implantation of a fertilized egg,” adding that to “suggest otherwise contradicts basic biological truths.”

John Charles Willke was born April 5, 1925, in Maria Stein, Ohio. He served in the Navy while pursuing his university studies, received a medical degree from the University of Cincinnati in 1948 and was an Air Force doctor in the early 1950s.

He and his wife began speaking together as participants in the Catholic Church’s Pre-Cana courses for soon-to-be-married couples. The Willkes later taught sex education and wrote the abortion handbook at the request of their daughters, who had encountered a disturbing lack of information at college, Dr. Willke told the Chicago Tribune.

His wife of nearly 65 years, the former Barbara Hiltz, died in 2013. Survivors include six children, Marie Meyers, Joseph Willke and Anne Millea, all of Cincinnati, Theresa Wilka of San Francisco, Charles Willke of Kenosha, Wis., and Timothy Willke of Mountain Lakes, N.J.; a brother; two sisters; 22 grandchildren; and three great-grandchildren.

Dr. Willke and his wife at times hosted unmarried pregnant teenagers in their home. When discussing abortion, he emphasized that he did not blame the mother.

“We see the woman as a second victim,” he said on CNN in 1990. “She needs help, she needs support. The abortionist is the killer.”