You must not have kids. Small children walk around with one hand in their pants almost constantly for a period of a couple of years before the age of five. Boys and girls. Boys and girls like manipulating their genitals a lot, and it is only the freaked out intervention of parents that suppresses it. It isn't lack of exposure to it in our children or our childhood it is the early and horrified suppression of its expression in children by parents who are uptight, and to quote, who don't like blue schlongs or tits.
cgfsd (1238866) is right. The US discomfort with sex and its depiction is unique to the US amongst industrialized countries that I have visited, and counties like it where belief in God and church attendance are high, like Saudi Arabia or Malaysia.
In Europe, where I was raised, its very different. After nine pm on any network there, and this was true at least as early as 1974, sex is commonly depicted, including nudity, pubic hair, breasts, simulated sex with bare asses, etc. I assume it is simulated, anyway. And not in a pornographic way, I saw in broadcast plays when I was a kid over there, like Bouquet of Barbed Wire for instance.
America is really strange for a European, or at least an Englishman (or at least this one), in terms of how polarized attitudes to sex, and so many other things are. Its pretty sad when you are more sexually repressed and weird than the culture wrongly known for it.
It seems it is either puritanism or nymphomania, and not much in between in the US.
America is an extremely religious country compared to the UK and Western Europe, and the attitudes of that shrill and sexually repressed majority have a huge impact here on many things. Including what gets shown on broadcast television (not late night subscriber cable) and in the movies. Exhibit B: George Bush who would have been laughed into oblivion in any country in Western Europe. Here he was a good christian, and that apparently was enough.
I still find it all disturbing almost 25 years after coming here.
"A child is a person who can't understand why someone would give away a perfectly good kitten." -- Doug Larson