Chiao et al. BMC Public Health 2012, 12:527 http://www.biomedcentral.com/1471-2458/12/527 Page 5 of 10 Table 1 Sample characteristics for male and female college youth (percentage or mean), TYP Covariates at age 20 Total Premarital sex by age 20 (n = 342) No premarital sex by age 20 (n = 1777) N = 2119 Male Female Male Female Adolescent risky health behavior Adolescent's cigarettes use Smokers Non-smokers Adolescent's alcohol use Heavier drinkers Light drinkers Abstainers Peers characteristics Perceived cigarettes use of best friends Smokers Non-smokers Perceived alcohol use of best friends Heavier drinkers Light drinkers Abstainers Perceived sexual behavior of best friends Half or greater Less than half None or unknown Attitude toward premarital sex Premarital sex permissiveness, range 0–3, (mean) Stressful life and behavioral events Stressful school events Yes No Number of stressful personal events 2 or more 1 0 Deviant behaviors Yes No Psychological complaints (mean) Family SES Maternal education Junior HS or lower Senior HS College or higher Monthly family income <50000 50000-69999 70000 & above 7.8 92.2 4.2 21.2 74.6 21.4 78.6 5.5 22.2 72.3 12.6 27.3 60.1 2.5 13.7 86.3 16.7 27.6 55.7 31.0 69.0 8.6 42.2 35.7 22.1 35.2 29.7 35.1 32.7 67.3 16.1 32.7 51.2 58.8 41.2 19.4 36.0 44.6 44.3 34.9 20.8 3.0 17.9 82.1 25.9 31.6 42.5 63.7 36.3 9.2 47.6 30.8 21.6 30.3 26.9 42.8 12.3 87.7 5.4 30.8 63.9 23.8 76.2 7.7 26.9 65.4 40.0 36.9 23.1 2.9 28.5 71.5 42.3 23.9 33.9 30.0 70.0 11.7 42.2 41.4 16.4 38.6 26.0 35.4 7.9 92.1 3.8 23.3 72.9 25.5 74.5 5.3 24.3 70.4 7.3 26.3 66.3 2.6 11.1 88.9 11.7 27.4 60.9 42.2 57.8 7.1 40.4 36.7 22.8 33.3 32.3 34.5 1.5 98.5 1.8 15.5 82.7 9.2 90.8 2.3 16.7 81.1 6.4 25.2 68.4 2.2 13.0 87.0 15.5 27.3 57.3 14.3 85.7 9.2 42.6 35.1 22.4 37.6 28.7 33.8