Gender is a part of every persons identity and can be incredibly diverse and for most people is dictated by society, but really why should you care? Maybe because these people are oppressed. Maybe because gender outside of the societal norm has existed in many cultures for a very long time. Honestly? Why you care is your choice, but for Trans people struggling with their identity is not.
Not sure what your gender is? Check out the flowchart below for a push in the right direction. What you choose to label your gender is a personal choice, but some people like to use familiar terms such as below.