Abstract: Embodiments of the invention provide methods for predicting the onset of menarche, i.e. a females first menstrual period, through the measurement of salivary hormone levels (e.g. 17-? estradiol, testosterone, progesterone, and/or 17 hydroxy-progesterone (17-OHP)). In particular, the methods described herein enable a reliable determination that menarche will, or will not occur, within varied time intervals, e.g. 1 to 30 days, 1 to 45 days, 1 to 60 days and 1 to 90 days. Diagnostic kits and products of manufacture comprising the kits are also provided.