Table 1.

Demographics and Baseline Characteristics for Infants With XXY

	All (n = 20)	No Testosterone Treatment (n = 10)	Testosterone Treatment (n = 10)	P
Pregnancy and birth characteristics
Maternal age, y	35.5 ± 3.5	35.1 ± 2.7	35.9 ± 4.3	0.62
Race and ethnicity				0.99
Non-Hispanic White, n (%)	17 (85%)	9 (90%)	8 (80%)
Other, n (%)	3 (15%)	1 (10%)	2 (20%)
Reason for prenatal screening, n (%)				0.58
Advanced maternal age	13 (65%)	7 (70%)	6 (60%)
Elective	6 (30%)	3 (30%)	3 (30%)
In vitro fertilization	1 (5%)	0 (0%)	1 (10%)
Maternal weight gain in pregnancy, kg	16.1 ± 5.6	16.2 ± 6.6	16.1 ± 4.9	0.94
Gestational diabetes, n (%)	1 (5%)	1 (10%)	0 (0%)	0.99
Gestational age at birth, wk	39.3 ± 1.1	39.2 ± 1.0	39.3 ± 1.3	0.79
Birth weight, kg	3.22 ± 0.42	3.35 ± 0.39	3.09 ± 0.44	0.17
Birth length, cm	50.7 ± 1.9	51.1 ± 1.6	50.4 ± 2.1	0.42
Infant characteristics at enrollment (baseline)
Infant age, d	72 ± 22	70 ± 23	73 ± 22	0.80
Feeding method				0.63
Breastfed only, n (%)	14 (70%)	8 (80%)	6 (60%)
Formula or combination, n (%)	6 (30%)	2 (20%)	4 (40%)
Total body mass, kg	5.4 ± 0.8	5.4 ± 0.7	5.3 ± 0.9	0.76
Length, cm	57.8 ± 2.9	58.6 ± 1.8	57.0 ± 3.6	0.21
FFM, kg	4.3 ± 0.5	4.3 ± 0.5	4.2 ± 0.5	0.55
FM, kg	1.1 ± 0.4	1.1 ± 0.4	1.1 ± 0.4	0.88
%FM	19.8 ± 5.1	19.7 ± 5.9	20.2 ± 4.6	0.75
Stretched penile length, cm	2.7 ± 0.5	2.8 ± 0.6	2.7 ± 0.3	0.43

Data presented are mean ± SD or number (%).