Maybe it's because of an ad on the Metro, or a billboard by the road. Maybe it's due to a Super Bowl commercial. But with mobile games spending big bucks for prominent advertising, it may only be a matter of time before your kid pesters you about an app they want to download, before you get a chance to even understand if it's appropriate for them.

Earlier this week, Google made two quiet changes to its Google Play store to address that problem. It announced publicly that it was pre-screening apps before publishing them on the app store. Second, it also said that, starting in May,  it would adopt widely used video game ratings to offer more information to users -- particularly to parents -- about what's actually in the apps they download.

They're small but significant moves to make Google Play more family-friendly and fall in line with recent changes to streamline the Google Play store as well as a broader effort at Google to produce more kid-friendly fare such as YouTube for Kids. But parent groups say that it's just a first step to helping families make informed choices about what apps are appropriate.

In some ways, Google is late to the rating party. Apple famously (or infamously, if you ask some developers) is known for taking its time reviewing apps before they publish in the App Store. Google Play, meanwhile carries the reputation of being a little more "buyer beware" but also a place where developers can move more quickly with a variety of app that mirrors the diversity of devices that run Android.

Google so far has let developers assign their own vague ratings to apps, rating them as either high, medium or low maturity. (Apple gives age ranges.) Now, developers will be asked to answer a questionnaire when they submit an app that determine ratings based on the standards of several international industry and government rating groups. The appropriate rating board's grade will show up on the store, depending on where you download it. That includes the U.S. video game industry's Entertainment Software Ratings Board, as well as foreign authorities such as Pan European Game Information and Australia's Classification board. Developers can fill out one survey with questions about content, data use and other factors to find the right rating in each region.

Having that shorthand information on the app stores and on advertising -- think that "E for Everyone" or "T for Teen" rating in the U.S. --  may help parents make more appropriate decisions about what to get for their children, said Patricia Vance of the ESRB. This unified ratings questionnaire has already been up and running on Mozilla's app store for roughly a year. In that time, it's proven to be a good tool for both developers -- who no longer have to submit paperwork to several different agencies -- as well as parents, she said.

"It was scary trying to take what we do as humans and turn it into a questionnaire," Vance said. "But as ads [for games and apps] move offline, we have to have a standard way" of communicating what's in a game. ESRB also notes that its own studies as well as others from the Federal Trade Commission show that parents understand and use its rating system in their buying decisions.

All new apps and significant app updates will have to go through the new process, said Google Play project manager Eunice Kim. Older apps won't have to be resubmitted, but Google may clear out "unrated" apps over time, said Google Play apps and games director Purnima Kochikar. That could clean up Google's more unsavory sections of the Play store over time.

Still, parents may want to seek outside sources of information when looking at these games and apps, said Jim Steyer, chief executive and founder of the children's advocacy group Common Sense Media. Common Sense runs its own reviews of apps, evaluating them with a critical parental eye that looks not only at content but also at the effectiveness of educational apps and how much the apps encourage in-app purchases.

Steyer added that he thinks Google has taken a good first step, but he hopes more will come on this front. Parents need more information than what ERSB provides, such as the way the apps will affect kids at certain social or developmental stages.

"Fundamentally the issue is that it’s the industry saying 'we’ll police ourselves,'" Steyer said. "It’s better than nothing; it’s a very modest step. And this is not going to satisfy needs of parents and consumers."