>>40
Getting kicked in the nuts isn't even a tenth as painful as childbirth for most women. First-timers, though. Babies tend to get out more painlessly the second and third time. Don't forget that being in labour is a very long process, anything from half a day to more than a day.
There is massive tissue damage involved, the cervix not only dilates but also gets ripped up, and so might the vaginal canal. Sometimes more than that gets ripped up....
Apparently dozens of women a day (in my country) rip up their colon/anus in the process of giving birth, according to statistics from 2004.