If the family has only daughters t does not mean that the women has the genetical defect .To say actually the gender depends upon man if the sex chromosomes are XX there will be a girl if the sex chromosomes are XY then it will be a boy
males have XY chromosomes
females have XX chromosomes\

is the sperm Y enters the mother cell it will be a boy and if X chromosome enters it will be a girl
The family has a daughter girl only because the zygote which takes the x chromosome from the father will be a girl and the one which takes y chromosome will be a boy.