Representative 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 Mr. Akin said, has surfaced periodically among anti-abortion advocates over the past two decades, usually involving the term “forcible rape” to refer to what Mr. 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,” Dr. 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.”