I don't know who you show KSP too.I can't talk for girls either as Tiberion already said but i see my sister play KSP from time to time. She is not the best at it but she is very interested in the game. She thinks Kerbals are cute and doesn't like to loose them in Accidents. Never has she asked why all Kerbals look male nor if female Kerbals will come to the game someday. She plays KSP for its concept and gameplay not for the Characters.