Re: brith control and comdoms together?
Well, as you have already done your research, you know that no birth control alone is 100% effective (except abstinence of course!). But I would have to say that doubling up on birth control just makes your odds of staying pregnancy-free that much better. It still is not 100%, there's always human error and product error. But the odds of getting through two forms of birth control (when both used properly) is probably extremely tiny. I would say if you are taking the pill correctly and you use a condom properly, your chances of getting pregnant are under 1%. (But it can still happen! So be prepared regardless!)
I say that if someone doesn't want to get pregnant but still wants to have sex, this is the best option. I highly encourage doubling up on birth control. There's always that chance of pregnancy (or STDs) so why even take the chance? Lower your chances as much as possible.
Basically, anyone who has sex should aware of the consequences. In my mind, if you are having sex, then you have accepted that you may get pregnant. Some people say "but I used birth control...it was out of my hands!" No, it is never out of your hands. If someone has chosen to have sex, they have chosen to accept the thousands of consequences that come out of it, no matter how many precautions they take.
Just my social rant on the subject!