There are laws that prevent the collection of private information such as name and email addresses of children younger than 13 years old. There are so many applications available on smart-phones today, the risk of some not following this law is high.
This article describes a pentalty assessed to at least one moblie app company for marketing to young children. Child safety relating to these applications affects more children than you might think. Neilson suggests 56% of parents use smart phones to appease grumpy children.
The best way to protect your children from these applications, is to be the one to download them onto the phone. Each application on an Android application must tell you explicitly if it will require access to your contacts, social media, or photos.
Legislators want all apps to reveal to all users what they will tap into and to how much advertising you will be exposed.