At a talk I attended over dinner a couple of days ago, this doctor (who having spent 20 years studying his passion, female urinary incontinence, shall remain nameless) said that between 20-50% of all adult women suffer urinary incontinence of some kind and that a study in Finland (or was it Sweden?) showed 30% of women who have had a child through vaginal delivery had significant incontinence.
One interesting point was in the discussion of the anatomy of the female pelvis. Take a look at the ceiling above you. It is help up by the sides and the beams that run across it above it at two or three foot intervals. Now, if the room were an analogy of the human female vagina, there would be supports on the sides but no beams above the ceiling, although there are beams below the floor. This was said to be because evolution has not caught up with humankind moving from being four-legged to standing on two feet. Why? The normal vagina is slightly tilted upwards in the standing woman. Now, imagine it turned 90 degrees forward and the supporting anatomy makes sense.