My parents talked to me and my siblings about sex. They must have done it gradually, in bits and pieces, because I have no memory of first learning about what sex was. We read the Bible aloud as a family (dedicated Christians), and, well, sex comes up, so that would have had to be discussed at some point.
Later, in my teens, they gave me and my siblings sex education/contraception talks, informing us of the pros and cons of different options and the fact that while they hoped we'd refrain from sex until if we got married, they knew we might not and if we didn't, they wanted us to know the options. This was always embarrassing and awkward, but I think I recognized even at the time that it was a good thing.
(We were homeschooled, so I didn't get school sex education.)
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Now convinced that I'm a bit autistic, but still unsure if I'd qualify for a diagnosis, since it causes me few problems. Apparently people who are familiar with the autism spectrum can readily spot that I'm a bit autistic, though.