Slow-wave sleep, or ‘deep sleep’, is intimately involved in the complex control of the onset of puberty, according to a recent study accepted for publication in The Endocrine Society’s Journal of Clinical Endocrinology and Metabolism (JCEM). The many changes that occur in boys and girls during puberty are triggered by changes in the brain. Previous studies have shown that the parts of the brain that control puberty first become active during sleep, but the present study shows that it is deep sleep, rather than sleep in general, that is associated with this activity.