Lightroom provides several levels of organization. The first is the Catalog. For the basic user, there will only ever be one Catalog. However, as an enlightened photographer parent, you can use Catalogs to your advantage. The main thing to remember about Catalogs is that you can only have one Catalog open at a time. So, while you can freely move between photos in different folders or collections, moving to a different Catalog means leaving the one you are in. The only way to get to a photo in another catalog is to import it into the catalog you are using. Thus, catalogs are for hard and fast separation.
Different catalogs are best used for different kinds of photos. So, for example, I have a catalog that has all the photos I take for my artistic purposes, a catalog that has all the photos that I take to sell as stock photographs, a catalog that has all the photos I take in my portrait studio, and of course, a catalog for all of my family photos. As a parent, keep all the family pictures in one catalog. Everything else can go in other catalogs.