I blame our educational system. Sexual education is a very recent thing and, despite the fact I have no idea what the hell is talked in such classes, I'm pretty sure they are doing a very bad job considering how ignorant about basic stuff people are.
And we didn't have biology classes unless you picked science in the last three years of school before you go to an university, which means, the majority of kids only got the basic of basics the human body functions (when I was in school we just learned things about the circulatory and respiratory system lol) that was talked in "natural sciences" that was supposed to teach us everything about live on earth, in 4 or 5 years of school... So my "generation" and older ones are completely ignorant about basic stuff unless they went to university or learned about it themselves.
Fortunately, things are different now. Kids learn about reproduction and hormonal systems as well as some bases of genetic, in the 9th year. Not all hope is lost lol.
I don't really have room to talk, yesterday I learned that some boats are made of steel and still float? What is science