Their is a big difference between ones sex and their gender. Your sex is biological i.e. male or female. Your gender is cultural/social i.e. man, woman, boy, girl. Take transsexuals for example. Lets say someone is born male but lives the lifestyle of a "woman." Are they a man or a women? They would be a woman with male reproductive organs. Since the two aren't really "accepted" or "commonly" put together, they get a title, like transsexual. Some cultures have as many as 11 genders!
Courses I have taken