I remember reading a short story about someone who travels to the/a future where everyone is equal.

It was discovered that equality could only be achieved if everyone looked identical (they found people with blue eyes considered themselves superior to people with brown eyes), everyone wore the same clothes (some kind of grey) and males were indistinguishable to females. There was also something about humans being selected for reproduction.

I am drawing a complete blank as to who it was, or what it was called, and Google isn't helping.

Any ideas?