@888
I think you are a little misinformed as to what condoms protect you from as well as how STI's are transmitted.
So let me start with something very simple.
What does a condom do?
Most people will go on some long ass answers here. The answer is actually quite simple. It captures male ejaculate. That is all that it does. Now ask yourself what are the benefits of capturing male ejaculate and what are the ramifications of NOT capturing it.
Not capturing the ejaculate exposes the woman, if it is deposited into her vagina, and she is ovulating, pregnancy. If she is not ovulating, she will not get pregnant. Now what else is in male ejaculate? Oh . . . HIV. HIV is a blood borne disease and needs to go blood to blood to transmit. Now the interesting thing about HIV is that if you are HIV+ and have a wide open sore and I pour HIV+ blood into it, you may or may NOT get HIV. It is not a binary thing where it happens all the time.
Does the condom protect you from anything else? NO.
Gonorrhea, Syphilis and Chlamydia are passed by skin to skin contact. It is bacterial based and likes that area. HPV and HSV are also skin based. So if you want to protect for those, I suggest the condoms that were used in the movie Naked Gun. That way you will be protected.
Before you start claiming BV as a STI, personally I think the CDC is fucked there. If a woman can get BV just by taking antibiotics and thus fucking up her PH, that is not a STI. There was no SEX involved!
But seeing you want to play numbers . . .
How many people are sexually active in the US? 200 million? Want to give them having sex once a week as an average? That is 10.4 billion times that sex occurred. What did the CDC report for HIV new cases last year? Wasn't it like 30k and of the 30k, about 10k was from hetero acts, the rest was needles and m2m contact. So now we have 10,000 cases out of 10.4 billion acts. Yes, this is really the one in a million odds.
But let's talk about something else that is more apropos: Stigma. Why is there such a stigma? You are more apt to get a cold or a sore throat from the exposure to people at parties. Those can fuck you up for a few weeks. Get gonorrhea, syphilis, chlamydia and you can be cured within a week by taking a Z-Pack.
Condoms are also effective in one other aspect that can not be measured: Peace of mind. If they give you peace of mind, congrats, do what makes you happy and comfortable. But when you think that they are protecting you from anything . . . well . . . not really.