there is an irony in sex education....telling kids "where babies come from" is one thing, but dealing with proclivities (that which turns on the biggest sex organ of all: the brain), is quite another......and is it freally something they need to be informed about? except that it's nothing to be worried about, unless the procliviies are encroaching upon the unacceptable (criminal) realm.
we do not turn into sexual beings at the moment the clock strikes midnight on the day we turn 18 (or, in some states 19)....we are born sexual beings, that is a bio/psycho/anthropological fact.
funny thing, a while ago (actually, quite a while ago) i searched wikipedia for entries in the "nude modeling" area and via a number of entries, i ended up in the pornography aisle, where i had free access to a free porn site: youporn.com........i believe that link has since been removed, but for a while any kid could have accessed the most explicit porn through wikipedia.
sexual pleasure, sexual expression are natural phenomena of the human being, there is somehow a code of "acceptable" sexual expression in our society and we as parents need to guide our children to appreciate the right balance, and to accept that some behaviours are not only unacceptable, but open to societal condemnation (criminal) as well.