"Gender" is what someone on the inside feels like they are, wether boy, girl, none, or both. "Gender" is a stereotypical thing.
Biological sex is what someone is born with, either girl or boy. You can't really change that.
So yes, people can identify as what they want. For example, let's say if a baby was born, and it was a girl. 14 years later, she's not into girly things, more of a tomboy.
Her biological sex would be female, and her gender would be boy.
Or, someone can be born a boy. Years later, they're a mix of everything. Some days they like girly stuff, some days they feel like a boy, some days they feel like none, and others they feel like bith girl and boy. Their biological sex would be boy, but their gender would be "Genderfluid".
A girl doesn't need to waste a lot of money to be a boy. If they dress and act like one, their gender would be "boy", stereotypically, it'd be called "tomboy."
A boy doesn't need to spend a lot of money to look like a girl if they feel like one, either.
They can if they want, but their gender would always be how they act and feel like.
I'm personally genderfluid. Sometimes I feel girly, sometimes boyish, sometimes both, sometimes none. However I was born female.
I feel like this meme can offend some people who just want to be who they are without being made fun of due to modern-day stereotypes that people follow. So I just wanted to put this out there, not to start a fight or anything, but I feel like some people needed to know this.