The time it would take me to elaborately say what I think about gender is summed up quite well in this article.
Journalist Jay Michaelson does a great job scaling from Kansas Republican Party anti-transgender resolution to the clarity of bible characters who's gender was not characteristic of their sex.
Why try to say something if someone already said it perfectly!
"Remember, sex is not the same as gender. Definitionally, sex is about chromosomes; gender is about cultural practices. Sex is what is between our legs; gender is what is between our ears. My male sex means I can grow a beard; my male gender means it’s socially acceptable for me to do so – but not, in conservative societies, to wear high heels and makeup. Of course, there’s nothing objectively male or female about shoes and clothes; they are aspects of gender, and they are socially constructed."
https://www.thedailybeast.com/what-does-the-bible-teach-about-transgender-people
Credit to Jay Michaelson for this work!