What is the difference between sex and gender?

Sex = male and female

Gender = masculine and feminine

So in essence:

Sex refers to biological differences; chromosomes, hormonal profiles, internal and external sex organs.

Gender describes the characteristics that a society or culture delineates as masculine or feminine.

So while your sex as male or female is a biological fact that is the same in any culture, what that sex means in terms of your gender role as a 'man' or a 'woman' in society can be quite different cross culturally. These 'gender roles' have an impact on the health of the individual.

In sociological terms 'gender role' refers to the characteristics and behaviours that different cultures attribute to the sexes. What it means to be a 'real man' in any culture requires male sex plus what our various cultures define as masculine characteristics and behaviours, likewise a 'real woman' needs female sex and feminine characteristics. To summarise:

'man' = male sex+ masculine social role

(a 'real man', 'masculine' or 'manly')

'woman' = female sex + feminine social role

(a 'real woman', 'feminine' or 'womanly')