Rep. Todd Akin’s assertion that women who are victims of “legitimate rape” rarely get pregnant provoked outrage across the political spectrum, but the views he articulated are far from new in anti-abortion circles.

The idea that during rape, “the female body has ways to try to shut that whole thing down” to prevent pregnancy, as Akin said, has surfaced periodically among anti-abortion advocates over the past two decades, usually involving the term “forcible rape” to refer to what Akin called “legitimate.”

Dr. John C. Willke, a general practitioner with obstetric training and a former president of the National Right to Life Committee, was an early proponent of this view, articulating it in a book originally published in 1985 and again in a 1999 article. He reiterated it in an interview Monday.

“This is a traumatic thing — she’s, shall we say, she’s uptight,” Willke said of a woman being raped, adding, “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.”

Leading experts on reproductive health, however, dismissed this logic.

“There are no words for this — it is just nuts,” said Dr. Michael Greene, a professor of obstetrics, gynecology and reproductive biology at Harvard Medical School.

Dr. David Grimes, a clinical professor in obstetrics and gynecology at the University of North Carolina, said, that “to suggest that there’s some biological reason why women couldn’t get pregnant during a rape is absurd.”

Akin’s statement did have supporters. Bryan Fischer, director of issue analysis for the American Family Association, a conservative Christian group, defended Akin on his program “Focal Point,” citing “John Willke, who is an M.D. by the way — a lot of these ignoramuses on Twitter are not.”

He read from Willke’s 1999 article, which described what is “certainly one of the most important reasons why a rape victim rarely gets pregnant, and that’s physical trauma.”

He continued with the article: “To get and stay pregnant a woman’s body must produce a very sophisticated mix of hormones. Hormone production is controlled by a part of the brain that is easily influenced by emotions. There’s no greater emotional trauma that can be experienced by a woman than an assault rape. This can radically upset her possibility of ovulation, fertilization, implantation and even nurturing of a pregnancy.”

Fischer concluded: “In other words, ladies and gentleman, Todd Akin was exactly right.”

Rep. Ron Paul, an obstetrician who ran unsuccessfully for the Republican presidential nomination, was asked about the issue Monday. “Rep. Paul has no comment,” a spokeswoman said by email.

Willke asserted that “way under 1 percent” of rape victims become pregnant, not just because of female biology but because about half of rapists “do not deposit sperm in the vagina.”

That, Willke said, is because many rapists have “a preference for rectal intercourse over vaginal;” experience “premature ejaculation, which is a major factor;” or “some of these guys just plain aren’t fertile.”But several experts said there is no solid data on such issues. A 1996 study in the American Journal of Obstetrics and Gynecology, generally considered one of the few peer-reviewed research efforts on this subject, estimated that 5 percent of rapes result in pregnancy.

“Yeah, there are all sorts of hormones, including ones that cause your heart to beat fast when you’re frightened,” Greene said. But he added, “I’m not aware of any data that says that reduces a woman’s risk of getting pregnant.”

As for the contention that a rape victim’s fallopian tubes tighten, Grimes, formerly of the Centers for Disease Control and Prevention, said, “That’s nonsense. Everything is working. The tube is very small anyway and sperm are very tiny — they’re excellent swimmers.”

© 2012 The New York Times Company