Quote from: Ryan on July 09, 2010, 04:32:34 AMT will stop your periods, but there's always a chance you'll get pregnant, even after years on T.
Exactly this, but so much more. I became acquainted with a young gay guy in WA who'd just gotten into a relationship. He had been on the depo shot for quite a while, given by someone who was not an endocrinologist. Surprise pregnancy time!
In someone who is not trans, ie everyday fertile female woman, having excess T or E can cause hormonal BC to fail. IUC/IUDs work primarily to make the uterus inhospitable -- supposedly the lining never fully matures, so it is WAY less likely to fail than the pill or the shot. If you're not going to use condoms (which you should be using!!), copper IUD is next-best, followed by diaphragm and spermicide combo. If you really want to prevent "miracle baby," you could use condoms with IUD or IUD with diaphragm and spermicide.
If you're having sex without a condom, you not only need a full STD test for both you and him, but also a pregnancy test monthly (if you don't have monthly periods).
I'm very pro-condom because the only person I've known who contracted HIV was a woman who got it from her straight husband. If you don't use condoms, you really have to be responsible with testing regularly. I use condoms with my girlfriend because it eliminates the risk of infection (although I do test, my GF does not).