The proportion of US high school students who report having had sexual intercourse has decreased, especially among black and Hispanic students, researchers say.
"More work is needed to understand the causes of these decreases and to ensure they continue," write Kathleen A. Ethier, PhD, and colleagues, from the Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia.
People who start having sex early in life are more likely to have sex with many partners, not use condoms, catch sexually transmitted infections, and get pregnant, the researchers report.
From 1995 to 2005 the proportion of high school students who reported having had sex declined from 53.1% to 46.8%, but this change was not statistically significant.
To see whether any change took place after that, the researchers analyzed data from the CDC's national Youth Risk Behavior Surveys. The survey was anonymous and voluntary. It included the question, "Have you ever had sexual intercourse?" Students completed the survey during one class period.
The researchers mention several "shifts in various influences" that could have affected these trends: technology and social media, requirements and funding for education, "innovations in and federal resources for human immunodeficiency virus infection," sexually transmitted infections, and teen pregnancy prevention.
The researchers acknowledge several limitations in their research. First, the data apply only to those in high school. Second, the results depend on accurate reporting by the high school students.
Still, they write, the apparent drop in sexual intercourse among the youngest high school students is especially encouraging. And so is the sharp drop among black and Hispanic students, as previous studies have found them to have more sexual partners, use condoms less often, get pregnant more often, and catch more sexually transmitted infections than white students
