I don't think it has anything to do with genetics. I am the only one in my family that has PCOS. PCOS does run in families (of course, almost anything does), however, there is no proof that it is hereditary. Usually, a woman with the condition will begin to experience menstrual irregularities within three to four years after her first period. Women may have other conditions, which cause irregular menstrual cycles or other symptoms, which mimic PCOS, but are not due to PCOS itself.