 And so the kind of most basic way to define sex for the plant and animal kingdoms is the reproductive strategy in which you have two differently sized sex cells, so-called gametes, ova and sperm, that fuse. And when they fuse, it produces a new member of the species. And the male's the one with the small mobile gamete sperm, and the female's the one that, at least under normal development, has the large immobile gamete, the ova. And then you have to take that into account. Then you have to take into account, okay, what about people with so-called disorders of sexual development, right?