Todd Akin is medieval in his thinking
That belief is medieval, and I don't mean figuratively. In Ian Mortimer's "A Time Traveler's Guide to Medieval England," which I reviewed a few weeks back, the author reported that this was one of the beliefs of the time. So if your wife claims she was raped, but she got pregnant, she had really been a willing participant, and hence an adulterer. So the real shocker is that Akin still believes this, 400 years of science notwithstanding.
In journalism, this is called burying the lead. Forget his poor choice in referring to "legitimate rape." The real message is that while liberals sometimes refer to conservatives as having "medieval" beliefs, in Akin's case it is not mere hyperbole.
It is also indicative of some conservatives' belief that when it's a choice between believing what your own prejudices tell you and what science tells you, believe the former (including that global warming isn't caused by man or is even real). It also is evidence of the so-called "Republican War on Science" (as Chris Mooney's book on the subject was titled).
This is a teaching moment, and it would be a shame if Akin drops out because of this. Sadly, his beliefs in the near impossibility of rape leading to pregnancy alone would not have been enough to do it.