What is the medical reason why some women can't conceive?
Ovarian cists can cause a woman not to conceive. As can a tilted uterus or certain sexually transmitted diseases left untreated. Cervical & uterine cancer left untreated can also cause this. (To name just a few)
There are many reasons why they could be infertile like a infection or injury
Too much testosterone, and not enough estrogen, to produce eggs that can be fertilized.
There are many different reasons which is partially why there are drs who specialize in this field of study.
I believe taking birth control for so many years but thats not a fact