Is it 100%? ie you have unprotected sex with someone with chlamydia, you get chlamydia too? Because if the chances of getting AIDS through heterosexual sex are apparently millions to one, what are the odds of getting chlamydia or other STI's? Are they quite low or quite high? Maybe something to do with AIDS being a virus versus most STI's being bacterial? Just wondering, can't find any info anywhere. Basically I had sex with someone, the condom broke but I was only 'exposed' for a few seconds. She got tested and she was clean. So does this mean that I must also be clean or not? Merci beaucoup.