Table 3. Percentage of cases of unprotected last coitus by sex, age group, and genotype among adolescents, United States 1994-2002.

	Males (N=1971)		Females (N=2092)
Genotype	Age ≤18 (N)	Age >18 (N)	Age ≤ 18 (N)	Age >18 (N)
DAT1
9R/9R	25.71 (35)	30.19 (53)	27.59 (29)	20.37 (54)
9R/10R	25.29 (257)	23.82 (382)	39.27 (275)	34.07 (408)
10R/10R	29.18 (490)	30.04 (669)	31.60 (519)	31.96 (751)
−/−	20.00 (40)	26.67 (45)	44.44 (27)	20.69 (29)
DRD2
A1/A1	15.63 (64)	22.22 (90)	29.87 (77)	20.83 (96)
A2/A2	27.70 (444)	25.73 (614)	33.49 (433)	31.14 (684)
A1/A2	29.30 (314)	31.91 (445)	36.47 (340)	35.28 (462)
MAOA
2R/−	37.50 (16)	45.45 (11)	58.62 (29)	48.39 (31)
−/−	27.17 (806)	27.68 (1138)	33.50 (821)	31.46 (1211)

Boldface indicates that the results are consistent with the following hypotheses: (1) DAT1*9R/9R respondents have lower rates of unprotected sex than other DAT1 genotypes; (2) DRD2*A1/A2 respondents have higher rates of unprotected sex than other DRD2 genotypes; and (3)MAOA*2R respondents have higher rates of unprotected sex than other MAOA genotypes. Formal hypothesis tests are presented in Table 4. The symbol ‘−‘ indicates an unlisted allele (e.g., neither 9R nor 10R for DAT1 gene).

Source: As for Table 1.