Biologically, anatomically, psychologically, mentally, and even in tastes and desires. They have different strengths and different weaknesses, and therefore, they will never be treated equally in society.
That doesn’t mean we can’t be treated fairly. The unfairness of it all is blatantly obvious in the comics down below. Artist have seen this, noticed it, and decided to do something about it. Look at the work below and share your own stories of societal double standards.