REMARKS

Serum concentrations of testosterone in both sexes during the first week of life average about 25 ng/dL. In male infants, values increase sharply in the second week to maximum (mean about 175 ng/dL) at about 2 months, which lasts until about 6 months of age. In female infants, values decrease in the first week and remain low throughout early childhood. Levels increase during puberty to adult values and are related to the pubertal stage rather than chronological age.