Amid debate over standards, kids have easy access to violent and sexual content.
Shoot zombies, watch their heads fly and blood splatter. Flick your finger and roll a virtual cigarette. Snap a photo and see what you look like with bigger breasts.
It's all possible from a smartphone or tablet, and most of those games littered with violence, vice and sex are at the screen-tapping fingertips of children -- often for free.
That's why mobile apps are the next frontier in the national battle over parental ratings. As app games explode in popularity, along with the devices that run them, industry leaders and watchdogs are jockeying for position amid debate over a standard ratings system -- much like movies and video games.
"The whole mobile world is a complete Wild West," said John Simpson of nonprofit group Consumer Watchdog.
App ratings vary by seller, with Apple offering different guidelines than Google's Android market, for example. Parents have questioned the validity of those rating categories, which are typically suggested by the app developers themselves. The mishmash gives parents one more thing to worry about when trying to keep adult content out of their children's hands.
"We must move beyond the alphabet soup of game ratings and consolidate behind a single standard that consumers will recognize and, ultimately, demand," John Riccitiello, chief executive of video game maker Electronic Arts and chairman of the Electronic Software Association, said late last year.
The discussion, already simmering, will grow louder as smartphones, tablets and apps multiply, adding to the deluge of current offerings.
In 2012 alone, Apple reported 20 billion app downloads -- equaling the number of apps downloaded in all previous years combined. The number of new apps being produced dwarfs the entertainment offerings by Hollywood and video game makers with 1,600 new apps debuting every day, according to some experts.
Both Apple and Google feature ratings suggested by app developers in their vast online stores. But the ratings are different in each "app market." Apple uses ages (4+, 9+, 12+ and 17+), while Google Play goes by maturity levels for its Android devices ("everyone," "low," "medium" and "high").
Critics have questioned how well parental ratings work. The American Cancer Society has criticized apps that promote tobacco use, some of which are rated 12+. "Nice Body," a photo simulator that cheekily shows what people are wearing under their clothes, is rated 4+.
If parents want to use Apple's guidelines, they can set their phones to prohibit downloads based on ratings. But, if those blocks aren't in place, Apple does not ask for age verification, except for apps marked 17+.
Case of 'baby shaker'
The most controversial apps do draw more scrutiny from app stores, usually after public outcry. For example, parent groups persuaded Apple to remove a "baby shaker" app that encouraged users to shake their phones until an image of an infant stopped crying.
The Entertainment Software Rating Board, launched by the video game industry to rate its own products, touts its app rating system as the best chance for a national standard.
"Consumers go from device to device," said Patricia Vance, president of the ESRB. "There's no reason they should have to use a different rating standard depending on the device."
ESRB, which already has buy-in from Verizon and Microsoft, asks developers to fill out a questionnaire about content and then assigns a rating. The giants of app distribution, Apple and Google, have spurned the ESRB's advances.
The ESRB ratings also indicate if an app shares its users' information with third parties and if it gathers location data.
Such privacy concerns have grabbed the attention of politicians in Washington, D.C., including Sen. Al Franken, D-Minn., who introduced a bill to prohibit "cyber stalking." The Federal Trade Commission has also clamped down on apps that share "personal information" from children under 13.
It's one thing for "the rating to tell you about the appropriateness of the content," said Simpson, who directs the privacy project for Consumer Watchdog. "But also of tremendous importance is the whole question of what data is gathered and how it is shared."
While the ESRB has dominated digital game ratings so far, there are others who offering competing guidelines.
Common Sense Media, a nonprofit group that helps parents gauge the child friendliness of media, offers alternate rating systems for video games and mobile apps. The group bases ratings on independent reviews and child development criteria, not on the app maker's opaque descriptions, said Shira Lee Katz, the group's director of digital media.
She said parents are looking for nuance and details, which can get lost in ESRB's ratings. "There are so many facets to an app," she said.
Missy Berggren, a local mom who blogs about parenting at www.marketingmama.com, tests apps before her 5-year-old daughter and 7-year-old son can play.
Even that isn't foolproof.
When Berggren went looking for a car racing app, she found one with good reviews. But upon opening it, she was surprised to see scantily clad female characters and violent crashes. She deleted it.
"I thought it was going to be just driving a car," she said.
As families navigate the digital landscape, a uniform rating system would help, she said.
"The technology is still pretty new," she said. "It's not like we've had a whole lot of time to get used to the concept of what the marketplace is and how it works."
Katie Humphrey • 612-673-4758