In the design world, human anatomy is important. For instance, if a designer is making something to be held by a hand, there are measurements for every dimension of the hand. And not just for one hand, the average hand, either — measurements exist for every dimension of the 5th and 95th percentiles of hand size as well. “But that’s just not available for designing sex toys,” Lieberman says. There is no corresponding data for vulvas. There is no official classification for the many different types of vulvas, and no sense of how common each type might be. Nor does anyone know how any particular vulva will react to a particular product. Take, for instance, a two-pronged vibrator: for many women, they won’t hit both the clitoris and the g-spot as promised. Sex toy designers don’t actually know the ratio that’ll work for most people: at best they’re providing an educated guess based on a limited sample of vulvas.