Table 1. Demographic characteristics of the study sample.

	Genotype	“Low” MAOA	“High” MAOA
	Count	n = 16	n = 18
	Age	29 ± 7.5	30.9 ± 7.5
Ethnicity	Caucasians	3	8
	African-Americans	9	7
	Hispanics	2	2
	Asian	1	0
	more-than-one race	1	1

The differences in the MAOA allele frequencies between the ethnic groups are not significant: χ2 = 3.85, df = 4, p = 0.43. Population-specific genotype frequencies are close to previously reported.