Differences between somatic growth curves of males and females are a secondary sex characteristic

There are differences in male and female height throughout the growth period. Utilising reference standard height charts we calculated the difference in male and female height as a function of age. A triphasic relationship was observed with statistically significant peaks (males>females) at 8 months and 18 years and (females>males) at 11.5 years of age. Data for sex hormone concentrations during this period were collected from the literature. Computing a difference measure (males minus females) for androgen levels a similar triphasic curve was obtained. Positive peaks occured at 3 months and 18 years and a negative peak around 10 yeas. All three peak differences were found to be statistically significant. Peak differences in estrogen levels were observed at similar ages. Whereas peak differences in androgens were positively correlated with those for height, a negative correlation was found for estrogen. This implies that somatic growth is a secondary sex characteristic facilitated by androgens and inhibited by estrogens.