BACKGROUND AND OBJECTIVES:Few studies have explored the hormonal triggers for masturbation in infants and young children. Thus, we aimed to study the sex hormones and clinical profiles of masturbating infants and young children.METHODS:This case-control study involved infants and young children who masturbate and were referred to three pediatric neurology clinics between September 2004 and 2006 (n=13), and a similar control group. All children underwent basic laboratory investigations prior to referral. Other tests included electroencephalography (n=8) and brain neuroimaging (n=9). We measured dehydroepiandrosterone sulfate, 17-hydroxyprogesterone, free testosterone, estradiol, dehydroepiandrosterone, sex hormone-binding globulin (SHBG), and androstenedione in all participants.RESULT:The median age at the first incident was 19.5 months (range, 4-36 months); the median masturbation frequency, 4 times/day; and the median duration of each event, 3.9 min. The subjects masturbated in both prone (n=10) and supine positions (n=3); two subjects used the knee-chest position. All subjects showed facial flushing; 6, friction between the thighs; 5, sweating; 9, sleeping after the event; and 12, disturbance on interruption. EEG was abnormal in one of eight subjects tested, and neuroimages were normal in all of nine subjects examined. The case and control groups had comparable levels of all sex hormones, except estradiol, which showed significantly lower levels in the case group (P=.02).CONCLUSION:Masturbation in children seems to be associated with reduced estradiol levels, but not with other sex hormones. Further studies are needed to confirm our findings.