best interest of children

I live in Michigan. I would like to ensure that if anything should happen to me that my parents would become the legal guardians of my two small children. I am a single mother, never married. My name is the only name on the birth certificate and paternity has never been established. My fear is that if something would happen, that my children would become wards of the state.
What do I need to do? Any help would be greatly appreciated.

Prepare a Will, stating just what you said, and naming substitutes if your parents could not handle the kids.