It turns out there’s a reason why the age of the average mobile phone user continues to decline. While most mobile users may not realize it, their kids may very well be a bigger target of mobile marketing than they are.

As if the plethora of Dora The Explorer and Hannah Montana digital content, mobile applications, and decorated iPhone cases aren’t sufficient to illustrate how advertisers are continuing to skew to younger audiences with the mobile platform, consider how frequently children are spotted on their parents’ smartphones.

Mobile applications in particular are increasingly marketed to parents as effective mechanisms for occupying kids and warding off potential public tantrums. After all, while you can’t take a fleet of toys into the grocery store with your kid, you can take a veritable fleet of digital toys (apps) wherever your smartphone goes.

PBS (The Public Broadcasting Service) is among the latest to illustrate the mobile industry’s expanding reach into the children’s entertainment market. The PBS Kids unit is giving a tremendous push to both “Super Why!” and “PBS Kids Photo Factory,” two new iPhone apps that emphasize learning and early education.

Although PBS Kids has traditionally marketed content to preschool age children, now that preschool age children are quickly becoming adept at wielding mom or dad’s iPhone, PBS has a newfound incentive to unleash an entirely fresh slate of mobile apps and other digital content tailored specifically to the youngest audiences ever targeted via the mobile channel.

It’s a trend that seems poised to continue, if not escalate at a rapid pace in the months and years ahead.