A longitudinal study was made of the daily urinary excretion, on or near each birthday, of a number of C19 and C21 steroids in 9 healthy girls and 5 healthy boys aged 3 to 7 years. The amount of androsterone excreted by each individual increased slowly during the period of study but the absolute amounts varied greatly between individuals. The excretion of aetiocholanolone was greater than that of androsterone, contrary to reported findings in older children. Small amounts of DHA were found. Testosterone was found in only about 40% of samples; epitestosterone in 70 % and 11β-OH-androsterone in only 62 %. Cortisol metabolites were excreted in amounts which increased with age and all three metabolites of corticosterone were present in most specimens. 11-Deoxycortisol was found in about 50 % of the samples and THS in 63 %. The mean trend in the ratio of glucuronides to sulphates of the 11-deoxy-17-oxosteroids decreased with increasing age, but the 11-deoxy-11-oxy ratio of 17-oxosteroids increased as did the 5α/5β ratio of the C19 and C21 steroids.
No sex differences were observed. The excretion of cortisol metabolites showed a positive correlation with height and weight. 11-Deoxy-17-oxosteroids were positively correlated with the weight. No significant relationships between steroid excretion and skeletal maturity were found.