"When and Where Do Youths Have Sex?" asks the title of this Pediatrics research article. The answer is when the parents are away, the kids tend to play - at home.
Using survey data gleaned from six urban public high schools, including 1065 boys and 969 girls, the authors found that only 23 percent of kids reported that an adult was home every day after school. "Fifty-six percent reported being home after school without an adult present for 4 or more hours a day, including 38% who reported 6 or more hours a day."
This unsupervised time allows teens unprecedented opportunities to engage in "various high-risk behaviors," including having sex. The authors found a "strong relationship" between the amount of unsupervised time and sexual activity: "The greater the amount of unsupervised time, the greater the percentage of youths who had ever had intercourse (and who had had it in the past 3 months...)." Boys who were unsupervised for five or fewer hours a week "had a mean of 3.70 lifetime sex partners," while those left alone for five to 29 hours had an average of 4.20 lifetime sex partners, and those home alone for more than 30 hours a week averaged 4.68 sex partners (P < .001). Girls fared slightly better, with 2.12, 2.53, and 2.53 lifetime partners, respectively (P < .001).
More to the point, "On average, every 10 hours per week of unsupervised time was associated with 0.25 additional lifetime sex partners for boys and 0.07 additional partners for girls."
The authors report that, "[a]mong the respondents who had had intercourse, 91% said that the last time had been in a home setting, including their own home (37%), their partner's home (43%), and a friend's home (12%)." Boys reported trysting at their own home more often than girls (43% vs. 28%; P < .001), and girls corroborated this, with 59% reporting having had sex at a partner's house, vs. only 30% of boys (P < .001).
The authors discover tragic, yet predictable, consequences. Boys who were left alone after school for more than 5 hours per week were twice as likely to have chlamydia or gonorrhea as those who were unsupervised for 5 or fewer hours. Increased rates of tobacco use, drinking alcohol, and marijuana usage each were correlated with more hours left alone, especially among boys (teenage boys left alone for 30 or more hours a week: RR: 1.55; 95% CI: 1.02-2.35 for tobacco; RR: 1.62; 95% CI: 1.29-2.04, for alcohol).
The authors draw the natural conclusion: "Our study suggests that increasing supervision would reduce the opportunities for youths to engage in high-risk behaviors." Since the study limns a definite tendency for students to be engaging in these activities at home, perhaps we can improve on their conclusion, though: Parental supervision is what is needed.