(Reuters Health) - Those cute little apps your child plays with are most likely flooded with ads - some of which are totally age-inappropriate, researchers have found.

A stunning 95 percent of commonly downloaded apps that are marketed to or played by children age five and under contain at least one type of advertising, according to a new report in the Journal of Developmental & Behavioral Pediatrics. And that goes for the apps labeled as educational, too, researchers say.

Often the ads are intrusive, spread across in a banner or even interrupting play, said study coauthor Dr. Jenny Radesky, an assistant professor of pediatrics at the University of Michigan and the University of Michigan C. S. Mott Children’s Hospital.

Perhaps the most insidious ads are the ones you need to click a little “x” to get rid of, Radesky said.

“The little ‘x’ doesn’t show up for about 20 seconds,” she explained. “If you’re a 2- or 3-year-old you might think the ad is a part of the game. And you don’t know what to do. You might click on the ad and that could take you to the app store. Many of these ads require you to do things before the ‘x’ will appear.”

Some ads are for products that aren’t appropriate for kids, Radesky said. “I’ve seen banner ads for bipolar treatment in some of these apps,” she added.

One app geared to young children had a popup that linked to a political game showing “a cartoon version of Trump trying not to push the red button that will send nukes,” Radesky said. “My son asked, ‘what is he talking about, is he going to blow up the world?’”

One big problem with ads in apps aimed at very young children is the kids often can’t tell where the game leaves off and the ad begins. “There’s science to show that children aged 8 and younger can’t distinguish between media content and advertising,” Radesky said.

Radesky originally was working on a study to explore how parents use their mobile devices. After noticing the kid-oriented apps on the parents’ phones, she and her colleagues decided this was a topic that should be looked at.

The researchers scrutinized 135 of the most downloaded free and paid apps in the “age five and under” category in the Google Play app store. Among them were free apps with 5 to 10 million downloads and paid apps with 50,000 to 100,000 downloads.

Of the 135 apps, 129, or 95 percent, contained at least one type of advertising, which included use of popular cartoon characters to sell products, teasers suggesting the purchase of the “full” version of the app, and advertising videos that interrupted play to promote in-app purchases or purchases of other products.

“What we found,” Radesky said, “was lots and lots of advertising.”

The new findings “are frightening,” said Dr. Albert Wu, an internist and professor of health policy & management at the Johns Hopkins Bloomberg School of Public Health. “This strikes me as a Trojan horse for tots. Even being charitable to all these companies, I think these apps are deceptive at best and unethical at worst.”

Wu was especially disappointed to find “this even applies to apps labeled as educational. It’s giving ‘educational’ a bad name. And it really does beg for a bigger role for the government in regulation even if there are some voices out there calling for less government. I think it would be important for the FTC (Federal Trade Commission) to step in.”

The idea that there is so much advertising in the apps, “is giving me even more reason to want to restrict screen use in my own children,” Wu said.

The new findings have prompted advocates to file a complaint with the FTC. The Campaign for a Commercial Free Childhood, along with other child advocacy groups, plans to file the complaint in conjunction with the release of the study results.

SOURCE: bit.ly/2yFUz1k Journal of Developmental & Behavioral Pediatrics, online October 26, 2018.