FX in girls

FX affects girls way less then boys because girls have 2 X chromosomes and boys only have the 1. So with girls only one of the Xs gets affected and the other one is fine so it tries to bypass the affected one. Some times it is successful for the most part and that makes them a carrier only but other times not so much and they have a milder form of the symptoms. It is the same for ASD as for FX and any other disorder that has ties to the X.