There was a time, about two decades ago, when the rate of teenage pregnancies was one of the hottest of issues. Barely a week would go by without tabloid headlines lamenting their frequent occurrence. Then things quietly began to change.

In both Britain and America pregnancy rates for girls and women under 20 began to fall, and they have now been falling almost continuously for more than 20 years, according to figures from the Office for National Statistics (ONS) and the US Centers for Disease Control and Prevention (CDC).

Theories as to what caused the fall abound, from increased access to contraception, to the airing of MTV’s hit TV show 16 and Pregnant. (In 2014 researchers found that a 6% reduction in teen births in the 18 months following its broadcast could be attributed to the show’s success at talking to young people.)

Now, researchers at the German institute for the study of labour (IZA) have found another potential contributor: the spread of high-speed internet.

Melanie Guldi from the University of Central Florida and Chris Herbst from Arizona State University conclude that “at least 13% of the total decline in the teen birth rate between 1999 and 2007 can be explained by increases in high-speed internet access” in the US.

They hypothesise that the decline could be because of teens becoming less sexually active, or because of an increase in contraception use, or both together, although the data is not clear enough to distinguish between the two. They found a corresponding decline in STI transmission as high-speed broadband rolls out which could correspond to both. They also found no evidence that broadband access leads to changes in abortion.

The researchers used a dataset of broadband rollout from the FCC, combined with county-level information on birthrate for girls aged 15-19, resulting in 22,824 county-year combinations to compare.

They write: “Broadband internet has the potential to shape in powerful ways the nature and intensity of individuals’ social connections as well as the quantity and quality of information received on relationships and sexual health … Americans are increasingly turning to the internet for a wide range of advice on romantic relationships, sex, and contraceptive methods.

“Americans – including teens – are asking for guidance on everything from whether they should have sex with a certain individual and the most effective forms of contraception to how to deal with a cheating boyfriend. Teens, who now spend more time engaging with various forms of media – much of it on-line – than any other activity (aside from sleep), are particularly well-positioned to take advantage of new information and relationship landscape created by explosion in broadband internet.”

Reducing teen pregnancies is just one of the many plus-sides of increased broadband access. Recent research shows that better internet connections can increase monthly household income by £200 in developed households, by improving access to learning and working from home.

And on top of all that, cat videos load in seconds on broadband. Maybe that’s the real reason for the decline in teenage pregnancies: today’s teenagers are just too busy watching YouTube.