Aromatase which converts Androgen to Estrogen

in E5 Fundamentals of Gyn you have said that Estrogen is not reqd for development of Female ext Genitalia
Meanwhile in next chapter in topic Abnormal sexual Development XX karyotype : one of the cause is def. Of Aromatase which converts Androgen to Estrogen

In aromatase deficiency the androgens would not be converted to estrogen. So the presence of testosterone/androstenedione in female (which would normally not be there) is what would lead to the development of male external genitalia…I think that’s what it means.