STD and sex question

Just a few questions I have…

If you have unprotected sex with someone that has an STD like, for instance, genital warts or chlamydia (sp?), what are your chances of contracting it? Is it a 100% transfer rate, or is it like getting pregnant - theres a high chance but it doesnt always happen-? What about AIDS and HIV? Will having sex with someone who has AIDS guarantee that you will contract the disease?

Simple answer, no. AFAIR, there is no pathogen with a 100% rate of transmission. I’m sure if you looked you could find stats, but stats are stats…in a real world one-time event there are just too many compunding factors to give Vegas style-odds. The method of intercourse, the life cycle of the pathogen, the susceptible host’s innate immune function, etc…