Twenty advocacy groups filed a complaint against YouTube Monday asking the Federal Trade Commission to investigate claims that the site illegally collected data on children under 13.

“Google has made substantial profits from the collection and use of personal data from children on YouTube. Its illegal collection has been going on for many years and involves tens of millions of US children," according to the complaint led by the Center for Digital Democracy and Campaign for a Commercial-Free Childhood.

Under the Child Online Privacy Protection Act, companies are prohibited from collecting data about child users under the age of 13 without authorization, CNN reported . The law requires that parents be notified and their consent be received before data collection of these underage users can be collected.

Although a YouTube account cannot be created by anyone under 13, according to the video sharing site’s terms of service, an account is not needed to view videos. Children will often use their parent’s accounts to watch videos and it’s easy to lie about age when creating a Google account, which is required to create an account for YouTube.

Kid-focused channels have large subscriber bases, whether that’s from parental accounts that children use, or from accounts created by children who claim to be older than they are.

According to a Trendera research report , 45 percent of children between the age of eight and 12 have a YouTube account.

The complaint states that there are ways to target ads for children in the absence of an age group under 18, such as keywords related to kids such as “toddler” and “toy.”

"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."

Recently social media sites and other websites that require logins, namely Facebook, have come under fire for questionable levels of protection for users’ data and personal information provided to the website to create an account.

Facebook CEO Mark Zuckerberg is appearing before Congress this week to testify regarding the Cambridge Analytica breach that compromised the data of millions of Facebook users.