What iz d difference between sex and gender?

Chromosomes/brain: This is a complicated and important question. In general, we have male or female genitals. But many folks experience a mismatch between what their chromosomes say, and what they identify their gender to be. A transgender woman, for example, was born with male genitalia - but lives female, and may have surgery to modify her body by changing facial and genital features. Same for transmen. See wpath.

Very similar: Strictly speaking there are only two sexes male or female. That is defined primarily by chromosomal identity. Gender is a range of characteristics of femininity and masculinity. These generally go with the female or male sex. It can be a little more complicated so now you can have a chromosomally male identify himself, his gender as female and vice versa.

Being vs Bouncing: “gender is who you believe yourself to be and your sexuality is who you want to bounce it off of.” -andrew solomon. Solomon's recent book "far from the tree: parents, children and the search for identity" is a great read!