As long as there has been sex education, there have been sex education films. Since America's first class in 1893, over 100,000 have been produced. Sometimes instructive, often hilarious, and always excruciatingly awkward, they have led generations of abashed students to think of the act of love in terms of valves and plumbing. But as this documentary attests, beneath the fumbling exterior, their content brilliantly captures the changing moral and cultural attitudes that bore them.