I've done some research on google.com and found a couple things out. Recently I've been interested in improving my success with women. However I don't want to do that at the risk of my life. So I've been looking into the STD factor. It appears that approximately 75/10000 (0.75%) of Americans have HIV. Of that population, ~50% are black people. Which is a ridiculous number, since only 13% of people in the U.S. are even black. 35% are white, and 1% are Asian or something else. ~23% are women. I further read that for some people, condoms do not break, whereas others find that they break repeatedly. (Condoms in other words break because of usage, not generally because of manufacturing flaws.) I have never had a condom break, so I consider myself one of the "good" users. I'd say I've gone through at least 200 condoms. So lets say the likelihood for me of a condom breaking is (overestimating) 1/100. So let's say I am about to have a one-night stand with some girl. I ask if she's been tested. If she says "No," we don't have sex. She says she has been tested. Then we have protected sex. I could still get HIV if: 1) She was lying about being tested, and 2) She has HIV, and 3) The condom breaks, and 4) I get infected. ?% * 0.18% * 1% * ?% = ? * 0.0018 * 0.01 * ? < 0.000018 So a given one night stand will give me HIV with a probability of up to 18 in 1 million, or less than 1 in 55,555. That's also a pretty conservative lower bound. Don't take this post as medical advice. If I'm wrong and you die of autoimmune deficiency disorder I'll feel bad and you'll be dead. Do your own research and make your own decisions. Feel free to give me feedback however.