In Mecklenburg's original piece, he wrote that pregnancy resulting from rape "is extremely rare" and cited as an example Buffalo, N.Y., which had not seen "a pregnancy from confirmed rape in over 30 years." Other cities Chicago, Washington, D.C., St. Paul, Minn. also had experienced lengthy spells without a rape-caused pregnancy, Mecklenburg wrote.
The reasons were numerous: Not all rapes result in "a completed act of intercourse," Mecklenburg wrote. He added that it was "improbable" that a rape would occur "on the one to two days of the month in which the woman would be fertile."
Mecklenburg's third reason seems to have been picked up by Akin, who made his comments in a TV interview Sunday.
A woman exposed to the trauma of rape, Mecklenburg wrote, "will not ovulate even if she is 'scheduled' to."
But a host of other research disputes Mecklenburg's conclusions, both on the scarcity of pregnancy after rape and natural defenses to prevent conception.
"From a scientific standpoint, what's legitimate and fair to say is that a woman who is raped has the same chances of getting pregnant as a woman who engaged in consensual intercourse during the same time in her menstrual cycle," said Barbara Levy, vice president for health policy at the American Congress of Obstetricians and Gynecologists.
One widely accepted study suggests a 5 percent post-rape pregnancy rate, resulting in 32,000 pregnancies a year.
The report was from the Medical University of South Carolina and was published in the American Journal of Obstetrics and Gynecology and cited by the U.S. Centers for Disease Control and Prevention.
But placing an exact figure on post-rape pregnancy is problematic, primarily because sexual assaults are thought to be underreported. Another factor is the availability of over-the-counter emergency contraception, which can prevent fertilization when taken after intercourse.
One study from the journal Human Nature in 2003 suggests pregnancy rates are higher after a rape when compared with consensual sex because of the inconsistency of birth-control use.
Mecklenburg's article was one of 19 in a book called, Abortion and Social Justice, published a year before the U.S. Supreme Court's Roe v. Wade decision.
In supporting his claim about trauma and ovulation, Mecklenburg cited experiments conducted in Nazi death camps.
The Nazis tested this hypothesis "by selecting women who were about to ovulate and sending them to the gas chambers, only to bring them back after their realistic mock-killing, to see what the effect this had on their ovulatory patterns. An extremely high percentage of these women did not ovulate."
Finally, Mecklenburg said it was likely that the rapists because of "frequent masturbation" were unlikely to be fertile themselves.
The book was edited by a doctor and a lawyer, and funded by Americans United for Life, the major legal arm of the anti-abortion movement.
Americans United for Life was founded by Brent Bozell, a Catholic activist who wrote for the National Review.
On Monday, the Review's editors called for Akin to quit the race, saying there was "no evidence for Akin's biological claim."
The dissemination of Mecklenburg's article may have had more to do with the influence of the doctor's wife, Marjory, an early opponent of abortion rights who was a chairwoman of the National Right to Life Committee, an adviser to Gerald Ford's 1976 presidential campaign and director of the Office of Adolescent Pregnancy Programs in the administration of President Ronald Reagan.
Today, Fred Mecklenburg is the former chairman of the OB/GYN department at Inova Women's Hospital in Falls Church, Va. He did not return a call seeking comment.
Mecklenburg's article, and the statistics cited in it, have been used again and again in the decades since.
Hadley Arkes, Amherst College political science professor and senior fellow at the Ethics and Public Policy Center, cited the Buffalo statistic in his 1986 book, First Things: An Inquiry Into the First Principles of Morals and Justice.
"The number of pregnancies resulting from rape in this country is minuscule," Arkes concluded. "In addition, the fear induced by rape may interrupt the normal operation in hormones in the body of the woman, which in turn may prevent ovulation and conception."
That kind of scholarly declaration has proved irresistible to some politicians.
In 1988, Pennsylvania state Rep. Stephen Freind told a radio interviewer that the odds of a woman becoming pregnant after being raped "are one in millions and millions and millions." The trauma of the rape, Freind explained, causes a woman to "secrete a certain secretion, which has a tendency to kill sperm."
His source, Freind said, was a "Dr. Mecklenburg."
In 1995, North Carolina state Rep. Henry Aldridge told the state House appropriations committee that when women are "truly raped ... the juices don't flow, the body functions don't work and they don't get pregnant."
Christian websites such as Physicians for Life and Christian Life Resources also have posted a 1999 article by J.C. Willke, a physician who was president of the National Right to Life Committee in the 1980s.
"There's no greater emotional trauma that can be experienced by a woman than an assault rape," Willke wrote. "This can radically upset her possibility of ovulation, fertilization and implantation."
Jill Powell, a gynecologist at St. Louis University, said misinformation about pregnancy can add to the psychological stress after a sexual assault.
"If someone has heard that medically there's some reason they may not be at risk for pregnancy if they've been sexually assaulted," Powell said, "maybe it would deter them from disclosing information or seeking medical help."