Fig. 5: Plots of the male (blue) and female (orange) log-transformed datasets with separate mixed-effects estimates for each in (left) and then transformed back into the measurement domain (right).

Note in the raw measures the increase in variance with age due to accumulated developmental differences, and the more age-independent variance in the log measurement domain. In the log domain there is a consistent fixed separation of the volume estimates. This corresponds in the right plot to a fixed fractional difference in volume estimates from female to male maintained throughout the gestational period (see Table 1 for specific numerical estimates).