Be careful when picking out presents for your kids this holiday season! Toy-related injuries have increased by a whopping 40 percent since the 1990s, and doctors say one type of toy is mostly to blame: scooters and similar ride-on toys, USA Today reports.

Findings from the new study were published in Clinical Pediatrics and showed that during the past two decades, more than 3.2 million kids (about 149,000 cases per year) were sent to U.S. emergency rooms for injuries involving toys.

What’s more, according to the report, scooter injuries alone accounted for the vast majority, or 42.5 percent, of kids requiring admission to hospitals between 1990 and 2011.

The Consumer Product Safety Commission, which annually examines toy injuries, also named scooters as the most dangerous children’s toy in its last two reports.

To help keep kids safe, one child-safety advocacy group, Safe Kids Worldwide, suggested parents buy age-appropriate toys and protective gear, such as helmets and kneepads, alongside scooters and bikes.

Did you know most American youth are killed by injuries and violence? Click here to read more.