You can filter contents on Google Play to avoid downloading apps with Low, Medium, High Maturity. Do as follows to restrict your Android phone or tablet from downloading apps with different maturity levels:
1. Open "Google Play" App
2. Hit "Menu Button" and then select "Settings"
3. Tap "Content Filtering" to set the content filtering level
4. There you see these options: Everyone, Low Maturity, Medium Maturity, High Maturity, Show All Apps.
5. Marking each of them means: You allow these Apps with such rating to be downloaded on your Android device