Joss Whedon said this quote

Why aren’t you asking a hundred other guys why they don’t write strong women characters? I believe that what I’m doing should not be remarked upon, let alone honoured… Because equality is not a concept. It’s not something we should be striving for. It’s a necessity. Equality is like gravity. We need it to stand on this earth as men and women. And the misogyny that is in every culture is not a true part of the human condition. It is life out of balance, and that imbalance is sucking something out of the soul of every man and woman who is confronted with it. We need equality. Kinda now. 'So, why do you write these strong female characters?' Because you’re still asking me that ques