Ignore biology at your own peril. Manifestations of physical AND mental differences between male and female have been obvious to everyone.  Research in the last couple of centuries has revealed - to a limited extent - the role genetics plays in the development and operation of these sex-aligned differences in height, weight, bone density, muscle mass, aggression, sexual arousal, and so on.  

Science knows some of how hormones interact and some of what those interactions cause within males and females. The differences mentioned above make any physical competition requiring speed or strength between males and females obviously unfair and demonstrably unsafe for females.

Turning to the issue of requiring that females be provided spaces that are separate from and apart from the view of males to change clothes and address personal hygiene. Set aside the stress that women endure because of obvious ogling by men.  

Statistically, males commit the vast majority of violent crimes, and of those, crimes against females are overwhelmingly sexual in nature.  So, yes, girls and women need protected from pubescent and post-pubescent males - something that has been known and done for millennia.