Age variation and sex differences in genotypic effects on development have been found in studies of the development of height in humans. A recent study by Cousminer et al. (2013) of the development of height in several samples ranging in age from pre-teen to adult revealed five loci (near MAPK3, PXMP3, VGLL3, ADCY3-POMC, and LIN28B) whose effect on height related phenotypes (measured by standard deviation from age/sex mean) varied with age and sex as calculated for six ages between 8 and 20. At all five loci, sex effects were significantly different between males and females at least one age. Opposite effects in males and females were found for the loci near VGLL3 and LIN28B. Since that study included results from samples considerbly larger than the sample studied here, it was able to detect significant effect sizes at a p < 10−5 level which were smaller by a factor of two than the effect sizes presented in this study. A previous study of LIN28B (Widén et al., 2010, p. 778) showed opposite effects for sexes in two SNPs from about age
