Gender is not a social construct. Taking a biology class would only prove how different we are. 😆
I think you mean being identified as masculine vs feminine. Self identy is a feeling you have that is rooted in the soul, not in the physical.
It's no body's business to make judgment on life choices and personal opinions, certainly it is not a new topic but an old one that keeps coming up over again.
Look at animals for instance, there are gay animals in nature, for example the Male seahorses can have babies. Male penguins can take on female roles. And there are many other animals of the same gender whom have matted.