New screen rules for children from pediatricians Nearly 40% of babies under 2 have used a mobile device, according to new study Three-fourths of all children have access to mobile devices at home, study finds Doctors recommend no screen time for babies under age 2 Guidelines urge limiting electronic devices for older children to one to two hours a day (CNN) -- When I had my first daughter more than seven years ago, I was adamant: no TV until she was 2 years old and limited exposure after that. As a reporter, I had done enough stories on children and screen time, and knew full well that the American Academy of Pediatrics recommends no screen time for babies under 2. Then my second child came along, and I found myself, like so many moms, struggling to entertain my 18-month-old while nursing my newborn. Yes, that is when we discovered "Dora the Explorer." There were no iPads then. If there were, I most definitely would have let my older daughter spend time on one while I took care of her sister, and we would have had plenty of company, according to a new study. Read: What's wrong with using tech to distract kids? Nearly 40% of children under 2 have used a mobile device, a jump from 10% in 2011, according to a study by Common Sense Media, a nonprofit child advocacy group. "The number of kids under 2 years old who have used mobile media has increased almost fourfold, and as many children today under the age of 1 ... have used smartphones or tablets as all kids under 8 years old had done just two years ago," said Jim Steyer, CEO and founder of Common Sense Media. "These numbers make it clear that we are witnessing the development of the first true digiterati generation from the cradle onward," Steyer said. Read: U.S. parents not worried about kids' digital-media use The explosive growth in babies on iPhones and iPads comes just as the American Academy of Pediatrics releases updated guidelines on children and screen time, calling once again for families to discourage any screen use for those younger than 2. The doctors' group is also recommending parents limit the amount of total entertainment screen time -- television, movies, video games, Twitter, Facebook, YouTube, etc. -- to one to two hours a day. Referencing the new guidelines, an Associated Press writer joked #goodluckwiththat, which really drives home the point, because the percentage of kids from babies up to 8-year-olds who have used mobile devices has nearly doubled from 38% to 72% since 2011, according to Common Sense Media. And, a 2010 Kaiser Family Foundation study found, children between 8 and 10, on average, spent nearly eight hours a day using electronic media outside of school -- that's more time than they spend in school! How on earth are we going to get our kids to dial that back to one to two hours a day? One starting point might be for families to set ground rules, because I was surprised to learn that two-thirds of children say their parents have "no rules" about the time they spend with media. Read: How to cut your kids' cell phone addiction CNN's Kelly Wallace says, "I try to limit screen time to weekends, much to the chagrin of my daughters." I think back to a recent column I did on innovative ways parents were trying to curb their children's cell phone addiction: Moms such as Jennifer Alsip of Robinson, Texas, who would cut off the Internet on her daughter's phone once she reached her maximum data allotment; Ann Brown of Cleveland, who doesn't allow her 17-year-old son to have a cell phone; and Melissa Barrios, a mom of two in Ventura, California, who pays $5 a month for the ability to shut off her 13-year-old daughter's phone from 9 p.m. to 7 a.m. At first, it was kind of weird to her, because there's always this, 'Well, my friends' parents don't do that.' But it always goes back to the same thing. 'Well, we're not your friends' parents. We're your parents,' " Barrios told me. And that's the point. We, parents, can play a role when it comes to our children and electronic devices. I know it's probably easy for me to say since my kids are not in that "I must have a cell phone" age group. But still, I try to limit screen time to weekends, much to the chagrin of my daughters. Opinion: Is the Internet hurting children? The pediatrics association recommends that parents come up with a family plan for all media and set curfews for media devices the way Barrios, the mom in Ventura, does. Doctors also recommend parents monitor what websites and social media sites their kids may be using at home. According to Common Sense Media, three out of four children have access to mobile devices at home, and while traditional screen time (television, DVDs, laptop and video games) is down 31 minutes a day, mobile screen time is up 10 minute daily. "This research is a major wake-up call for parents, educators and the tech industry," Steyer said. The data reveal the rapid and profound changes in childhood and learning, and it is critical that we approach these major shifts in a truly ethical and responsible way for the long-term good of our children and our society.