Gender and sex? What's the difference?

What’s the difference between sex and gender?

Sex is a term that’s usually used to talk about a person’s biology. (e.g. what visible sex organs a person is born with, like a penis or vagina).

Gender refers to socially constructed concepts of what it means to be a woman or man or gender-diverse people. Gender identity is not binary (girl/woman, boy/man) nor is it static; it exists along a continuum and can change over time.