Etiology and evaluation of delayed sexual development

Normal puberty begins with an acceleration in somatic growth and the appearance of sexual characteristics. It progresses by closing the gap to adulthood as a new sexual awareness arises in the adolescent. This is accompanied by a gradual maturation of thought and emotional processes. At completion, puberty endows the female adolescent not only with an adult female physiognomy and presence of menses, but with the immediate capacity for reproduction. Variations in the normal time of onset, sequencing, and tempo of pubertal development are considerable. Guidelines for aberrant development can be established, based upon standard deviations from the norm. Delayed sexual development has previously been defined as the failure to initiate sexual development at that age which is 2.5 standard deviations from the mean. In females, absence of thelarche by age 13 may be the first sign of pubertal aberrancy. Causes responsible for delays in development may also interrupt puberty that has begun on time. The definition of delayed sexual development is therefore expanded to include any alterations in sequencing and tempo of pubertal development after thelarche. Ultimately it is the initiation of ovulation that establishes final pubertal maturity. An appreciation for the time onset, tempo, and sequencing of normal puberty is a prerequisite for identification of pubertal aberrations and their investigation.