Are we too old for sex education? Perhaps, but How Sex Works starts off with fun facts: men who choose wives with a pleasing waist to hip ratio are right (their children are smarter, it seems – hooray for big hips!); male bees suffer a gruesome (but entertaining, to us humans) death as they procreate; we humans tend to choose mates whose smell we like, and that seems to automatically select for a complementary immune system, hence healthier offsprings; and women appear to actually have prostates.
Unfortunately the last chapters revert to boring, boring standards such as using condoms to prevent STDs. Just stop reading when you get there.