The way I heard it, it's the aging/loss of muscle tone of a floor of muscles that support the bladder, which develops a weak spot between them. Thus this allows the bladder to hang down between them with not only no support, but pressure from the squeeze of the surrounding muscles. Treatment-- Kegel exercises.

I also heard there is a higher incidence of nerve damage in that area among women as they age, who had forceps deliveries in childbirth.

Fun, though, innit?

~S~