I know this is kind of old but I had to contribute.
1990s, Georgia, USA.
Elementary school:
If you have sex, you will get pregnant and you will probably get AIDS.
This is a legit scenario that one of the teachers described. I am not making this up:
If you're at a party, and eat a potato chip, that chip could cut your mouth. And then if you kiss someone else, you will get AIDS.
Middleschool:
A horrific slideshow of all the worst-scenario cases of all STDs you could ever get.
Also, if you have sex, you WILL become pregnant.
And, anything other than PIV was never brought up. I s**t you not. I had no idea what oral sex was until I was in highschool, and even then, I only knew about it because of the internet and sexually active friends. Nobody in any sex ed class EVER brought it up.
ADDITIONALLY, we never, ever touched condoms. We only talked about them. I see several people mentioning taking condoms home and s**t-- no, I never got that. We didn't even get that demonstration of condoms over bananas that happens in the movies.
I'll tell you what we DID get.
A GIGANTIC stuffed sperm, which turned into a group activity of the entire class holding the sperm. Then, a symbolic representation of a condom (which was like a donut).
"As you can see, Sammy the sperm cannot fit through the condom, but HIV (a penny) CAN."
So we were taught that if you use a condom having sex, maybe you won't get pregnant, but you'll still DEFINITELY get AIDS.
Highschool:
We dusted off the old slideshow of horrendous STDs in the worst-case scenarios, with the lies that all STDs ever were always this bad. But we got a new addition this year: We got to see the "Miracle of life" video, which if anyone was unaware, it is the most ugly-a** video you could ever watch of a woman giving birth to a giant bloody alien blob known as a human child.
By this time, Abstinence-only education was coming under heat, so we actually did talk a little bit about sex, mainly if you have it, use a condom, but there were still a lot of scare tactics and basically the ending message was, again, if you have sex, you will get pregnant and get AIDS.
So, I was ******** scared as s**t of sex. They never taught us about masturbation either. I didn't know what masturbation was. I just knew when I touched myself it felt good but that was bad.
Seriously, my sex life was pretty ******** traumatic when it finally happened. I cried during and after sex until I was 23 years old. Abstinence-only education was maddening and I think it should be criminal.
Elementary and middle school sex ed was full of misinformation and just blatant lies and scare tactics. By highschool we were finally getting "real" information, but it was presented in a very VERY misleading way.
Also, there is always the ability to "opt out" of sex ed. Parents have to OK sex ed in Georgia. Plenty of kids weren't allowed to go because their parents said no. They were sent to a study hall where they learned absolutely nothing about sex.
EDIT:
If you can read this infograph (they made it TOO huge imo), it goes through the timeline of abstinence-only education, and basically why states did it.
http://ncac.org/wp-content/uploads/import/AbstinenceOnlyInfographic2.png
tl;dr the government gave states who taught abstinence-only education a bunch of money.