Comment by setopt
> why would uterine lining cells outside the uterus lead to infertility inside the uterus?
The quoted text mentions for example the ovaries themselves, which if damaged can not release eggs, and the fallopian tubes, which if damaged can not transmit eggs from the ovaries to the uterus. These are outside the uterus.
According to my wife’s surgeon (she had endometriosis removed in 2008) there is some belief that the condition can actually cause the womb to become less hospitable to egg development, i.e. the fluids en utero actually weaken the health of the eggs.