Using the following settings, press "generate pedigree" (not "generate random pedigree") three to six times, and notice the frequency of affected sons and daughters in the f1 to f4 progeny.
settings:
mode of inheritance - x-linked recessive
parental generation -
male - nonmutant
female - heterozygous
matings between relatives - disallow
progeny in first generation - 4
show carriers - turn on
why aren't there any affected females in the f1 generation under these conditions?