In the context of gender, sex refers to biological differences between males and females. These are, for example, differences between the female/male chromosomes (female XX, male XY) and the reproductive organs (ovaries, testes). Gender, however, refers to the cultural differences expected (by society /culture) of men and women according to their sex. This means that while sex is a biological fact that is the consistent across culture, what sex means in terms of gender roles can be different.