I think that's one of those many, many things women aren't told will happen to them when they decide to breed. It's not even just anal incontinence - pregnancy and childbirth will destroy damn near everything in the pelvic area. Urinary and anal incontinence, pelvic floor damage, I'm sure hernias are common from all the pushing, not to mention the tearing that can leave a woman with a vasshole. That shit doesn't snap back and I can tell you that no child is worth shitting myself for the rest of my life if I cough too hard. If I want my asshole to leak all the time, I'll take Alli. At least I'd lose weight.
If women were told in explicit detail exactly what would happen to their bodies during pregnancy and childbirth, most of them wouldn't do it. Out of the ones who would still do it, probably at least 90 percent will tell themselves that those awful things only happen to other women, but they won't happen to them because they're special.