Well to be pedantic, your gender is who you are as defined by society's standards and mannerisms and such whereas your sex is what's defined by your genetics and between your legs...

Really? I always thought it was the other way around. Cause sex and sexuality

Really, your gender is in your head and your sex is what's between your legs. That's why we have people who are transgender - where the gender they are doesn't align with their physical sex. And I can see where you're coming from but I'd say sexuality was based on the sex of a person you want to be with... cuz we also have people who think someone is one sex because of how they look and upon finding out (if they find out) that the person doesn't have the organs expected then the person will be: even more attracted (tranny-chaser is the phrase I believe), disgusted - almost fair enough, if they like girls and find their crush has a dick then sure but don't be an asshole about it or they could just not care much...

So... Respect