SAN ANTONIO – Kids love YouTube. The service is packed with ostensibly kid-friendly content.
But child, consumer and privacy advocacy groups are claiming YouTube illegally collects data about underage viewers. They want YouTube to change how it handles content for children.
In a complaint filed in April, 20 advocacy groups asked the Federal Trade Commission to investigate the Google subsidiary for violating the Child Online Privacy Protection Act, which limits how a company can collect data about kids younger than 13. Under the law, companies have to notify parents and get their consent before collecting data on children.
(COPPA is "meant to prevent companies from collecting data about children and then using it to do things like target advertising to them without the parental consent," said Robert Richter, of Consumer Reports.
YouTube's terms of service says it's not for anyone younger than 13. To sign up for a Google account, which is used to log into YouTube, a person must say they are 13 or older.
But anyone can watch YouTube videos without an account or logging in. Parents can let their children use their accounts, or kids can lie and claim to be older when creating an account. According to Trendera research, 45 percent of kids between 8 to 12 years old have a YouTube account.
Kid-focused channels can have huge subscriber bases and make significant amounts of money on ads.
"You have to understand that these companies make their money by knowing who their viewers are," Richter said. "YouTube can tell the giant advertising machine behind it, 'These are definitely going to hit some kids and so you can show some specific ads there.'"
YouTube has a standalone mobile app for children, YouTube Kids, which it launched in 2015. YouTube says the app complies will all COPPA rules, and doesn't collect data for ad-targeting.
"Protecting kids and families has always been a top priority for us. We will read the complaint thoroughly and evaluate if there are things we can do to improve," a Google spokesperson told CNN. "Because YouTube is not for children, we've invested significantly in the creation of the YouTube Kids app to offer an alternative specifically designed for children."
Editor's Note: CNN contributed to this report.