Table 1.

Demographic characteristics of the study sample.

	Sex
	Male	Female
Panel A
Sample size (N = 325)	152	173
Age (years)a	11.00 (3.80)	10.87 (3.71)
AFIb ($)	69 656 (29 305)	75 261 (34 084)
Full-scale IQ	111.27 (12.8)	111.18 (11.7)
BMIc	19.07 (4.31)	19.41 (4.29)
Right handed (%)	85.43 (0.03)	90.17 (0.023)
Parental educationd
Less than high school	1	0
High school	18	11
Some college	33	38
College Degree	46	54
Some graduate school	9	13
Graduate school	45	55
No reported	0	2
Panel B
AFIb	<$50 000		$50 000– 100 000		>$100 000		Total
Sex	Male	Female	Male	Female	Male	Female	Male	Female	Total
Age (years)
4.8–6	2	6	11	3	0	4	13	13	26
6–8	6	10	16	20	8	5	30	35	65
8–10	5	8	14	12	4	7	23	27	50
10–12	4	10	17	14	0	11	21	35	56
12–14	12	1	10	10	4	10	26	21	47
14–16	9	6	9	10	4	5	22	21	43
16–18.3	6	7	6	9	5	5	17	21	38
Total	44	48	83	78	25	47	152	173	325
Panel C
Race/ethnicity of child	Male (n=152)	Female e (n=173)	Total (n=325)
American Indian or Alaskan native	3	2	5
Asian	2	4	6
Native Hawaiian or other Pacific islander	1	1	2
Black or African American	11	19	30
White	120	120	240
Mixed/unknown or not reported	15	27	42
Hispanic (of any race)	21	22	43

^aMean (SD).

^bAs originally reported by telephone interview and adjusted for family size and geographical region.

^cBMI, defined as mass (kg)/height (m)².

^dHighest level attained by either parent.