Abortion and breast cancer

Another thread got me thinking of this question:

Does abortion increase the likelihood of contracting breast cancer?

The logic is as follows: When one gets pregnant, the body’s hormones gear up to convert the otherwise inert breast tissue into lactation mode. If a natural miscarriage occurs, the body gears down this process.

However, if an othrwise healthy pregnancy were to be suddenly and artificially terminated, the hormones get thrown out of whack and some kind of feedback screws up the breast tissue’s DNA, sometimes triggering a malignancy.

Does medical research give any weight to this theory, or is it just Rabid Pro-Lifers spreading blatant lies to prey on women’s fears?

http://www.usatoday.com/news/health/2003-02-26-cancer-usat_x.htm
http://www.bcaction.org/Pages/DoSomething/NCI.html

Apparently the National Cancer Institute used to push this idea but was recently forced to come clean and admit it’s bunk.

Even if it’s true, medical science should surely eventually be able to correct the hormones, and simulate a natural miscarriage.

Speaking as someone whose mother and aunt both developed breast cancer despite never having an abortion, I find it medically interesting, but irrelevant to the pro-Life debate. There are many causes for breast cancer, and no matter how you live your life you cannot necessarily avoid getting it.