I’m pretty sure alot of people use it interchangeably to mean the same thing. But I think over the years, gender has become more of a “social” word and Sex as more of a “biological” word. I say Gender instead of sex when talking about someone’s biology. A bit confusing honestly for non-native English speakers

As an English speaker, trust me you don’t wanna know. Don’t dive into it

Funny enough, the Japanese doesn’t have the word “the” per say. It most depends on context and how you translate it. Example: ねこは赤です -> literal translation: Cat red Now time to add some English words to make it sound ✨better✨ “The cat is red”