Sex Vs. Gender

The words sex and gender are very similar in terms of differentiating men and women. There is difference between two of them though.

Sex: Sex differentiates men and women based on their anatomy. One is a man because he has testicles, and one is woman because she has ovaries. The word sex has to do with those physical differences. 

Example: Don't forget to enter your sex on hospital's application form. 

Gender: Gender is more of an identity that men and woman carry in society.

Example: Gender inequality has come down significantly in last fifty years.