I have a crazy question that requires a (crazy?) medical professional's attention. [View all]

I am curious what the chances are of a fertilized egg failing to attach itself to the uterine wall.


As I understand it (and I could easily be wrong) much of the fight over contraception is that medications are being used which prevents a fertilized egg from attaching itself to the uterine wall.


Because this sometimes happens naturally, and because no form of birth control is 100% effective, I would like to try and work out some numbers and try to present an argument that women are simply trying to increase the odds of this happening.


I know it sounds crazy, I admitted that up front, but because of the "life begins at conception" point of view from religious fundamentalists I think that can be countered with a "God does this to women all the time" argument.

Thanks for any help. When something like this pops into my head I just need to work it out, even if it ends up not making any sense.