For your morning amusement, we present this brain wrought from a watermelon. It was carved by Reddit user TheHerferd. And, if this is the kind of thing you'd like to do for yourself, Boing Boing has a few pointers to share.
The scenario many of us learned in school is that two X chromosomes make someone female, and an X and a Y chromosome make someone male. These are simplistic ways of thinking about what is scientifically very complex.