Integrated serum concentrations of luteinizing hormone have been compared among 30-minute collections from 10 boys (6–18 years old) and 5 girls (5–11 years old). This study suggests that prepubertal as well as pubertal boys have greater mean integrated concentrations of LH during sleep than during waking. One of two pubertal girls had greater concentrations of LH during sleep, while three prepubertal girls did not.