Gender is what you are between the ears, not the legs.
Gender is what you are between your ears and not between your legs. Sometimes this matches our sexual organs and sometimes it doesn't. Gender can be expressed much more fluidly. Sam Killermann explains the complexities of gender and the assumptions made. He encourages us to be gender creative in understanding and appreciating the variants of gender identity.
http://itspronouncedmetrosexual.com/2013/05/my-ted-talk-understanding-the-complexities-of-gender/