Polycystic ovary syndrome (PCOS), a leading cause of female infertility, occurs in approximately 4% of women of reproductive age. Multifamily studies have established that PCOS has strong inherited traits. Although diagnosis of PCOS in the relatives of affected women can readily be made by clinical and biochemical evaluations, these methods are costly and laborious. The aim of this investigation was to determine whether clinically evident PCOS could be detected by a written questionnaire, which is a significantly less expensive means of detection than direct determination. A questionnaire about the history of possible androgenic symptoms of PCOS was presented to patients and their first-degree female relatives, who were also evaluated by physical and laboratory examinations. The sensitivity, specificity, and positive predictive value (PPV) and negative predictive value (NPV) for the detection of PCOS by interview were calculated. The NPV of the proband interview was significantly lower for sisters than for mothers (82% vs. 100%, respectively; p < 0.05). When the family member completed the written questionnaire directly, the specificity and NPV of self-reporting were equally high (> 90%) for both mothers and sisters. Thus direct interviewing of PCOS patients or their mothers and sisters reliably predicts affected status, but patient interview alone will not predict PCOS in almost 50% of the affected sisters.