Birth Control 99.9% Effective?

Question

So if birth control is 99.9% effective, does that mean that I'll get pregnant 1/1000 times I have sex?

Answer 1

Favorite Answer

Most birth control is not 99.9% effective. However, if it had that level of effectiveness, then statistically 1 in 1000 women would get pregnant on it. That does not translate exactly to 1 in 1000 sexual encounters.

Answer 2

No. Google "probability" and you'll find out why.

It means that every time you have sex, you'll have a 1/1000 chance of getting pregnant.

Every time.

If you had sex 1000 times, you'd have a chance of 0.01% every single time.