Can a family friend put me on their car insurance?

So i live in the state of california. I have had my learners permit for more than six months now. I want to get my drivers license but due to the economic crisis my parents aren't able to pay every month to have me on their car insurance. A family friend has offered to put me on their car insurance, but what my parents want to know is if that is legal in the state of california or do I HAVE to be insured by my parents?