Genotypes were available for 3884 boys and 3627 girls. The allele frequencies of the 30-bp repeated sequence present in 2 (0.003), 3 (0.347), 3.5 (0.019), 4 (0.616), or 5 (0.014) copies were the same in both sexes. Enzyme expression is known to be 2 – 10 times higher for the 3.5 and 4 repeats than for the 3 repeat (Sabol et al, 1998). Therefore the 3 repeat alleles were classified as low activity (L) whereas the 3.5 and 4 repeat alleles were classified as high activity (H). The 2 and 5 repeat alleles were excluded because their activity levels are not yet clear. The genotype frequencies for boys were: L: 0.338 and H: 0.662; and for girls were: LL: 0.121, LH: 0.452, HH: 0.427. All genotype frequencies conformed to Hardy-Weinberg equilibrium.
