Each state has different laws and rules regarding insurance. There can be many correct answers to this question based on where you live. Verify that your passenger has medical insurance of their own, and that it does not exclude a motorcycle related injury. Contact your insurance agent or the company that insures your bike directly and ask questions.
Many times people do not ask questions before they ride. Ask if you have or need uninsured motorist coverage, medical payments, or more guest passenger liability. Remember each state is different and you need to be sure you ask questions first.