Especially now, when most public images of the human form are airbrushed into a preposterous lie, children ought to know what actual people look like under their clothes. Thanks to the internet, a generation of boys is growing up submerged in the fake aesthetic of pornography – as ignorant of real female beauty as the Victorian art critic John Ruskin, who discovered on his wedding night that women have pubic hair, and was so disgusted that he refused to consummate the marriage. Life classes, like naked parents, are a no-strings-attached opportunity to see what other people are really made of.