Objective: To determine whether disorders of insulin secretion are common in male and female family members of subjects with polycystic ovary syndrome (PCOS).

Design: Family study of siblings and parents of PCOS subjects (five families). All proband cases met the criteria of polycystic ovaries (PCO) by ultrasound (US) and hyperandrogenism.

Setting: University Reproductive Medicine Unit.

Patient(s): Family members of PCOS subjects.

Intervention(s): Oral glucose tolerance testing (OGTT), insulin, and lipids were measured. Clinical examination including assessment of premature baldness in men and US of ovaries in female members.

Main outcome measure(s): Insulin, lipids, and clinical parameters.

Result(s): Hyperinsulinemia (69%) and hypertriglyceridemia (56%) was common in family members as were PCO in 79% of 24 females and premature baldness in men in 88% of eight subjects.

Conclusion(s): Hyperinsulinemia is a potential metabolic and genetic marker for subjects who may be carriers of a familial tendency for PCO.