Across the U.S., the number of high school students who report having sex has dropped, according to new federal data.
The report, based on a nationwide self-reported survey of high school students and published by researchers at the U.S. Centers for Disease Control and Prevention (CDC), found that the proportion of students who said they had ever had sexual intercourse dropped from 47% in 2005 to 41% in 2015, the latest data available.
This decline in sex among high school students is likely a contributing factor to key recent trends: teen birth rates hit a record low in 2017, and teen pregnancy has been consistently dropping. The study authors say that more research is needed to understand the trend and to help it continue.
A decline in younger people having sex is a positive change for public health, according to the CDC. Having sex at an early age is associated with having more sexual partners overall, not using condoms, teen pregnancy and having sexually transmitted infections at a young age.
One reason for the drop is that fewer younger students—those in 9th and 10th grade—reported having sex, the researchers noted. They did not see a drop in sexual activity for 11th and 12th grade students. Fewer black students in all grades said they had sex, and fewer Hispanic students in three grades said the same. “[This] represent[s] positive changes among groups of students who have been determined in previous studies to be at higher risk for negative outcomes associated with early sexual initiation,” the researchers write.
Though the study does not look at potential reasons for why fewer young people are having sex, the researchers note that a lot changed in the U.S. from 2005 to 2015, including a proliferation in technology and social media use as well as requirements and funding for education in preventing teen pregnancy and sexually transmitted diseases. Other federal data shows that most teenagers are now using contraception when they have sex.