What is considered to be a parent or guardian?

If a seventeen year old wanted to donate blood but was unable to get a signature from a parent, would he or she be able to get a signature from an eighteen year old freind? The signature form asks for ';Signature of Parent or Guardian.'; I don't know if the laws differ state by state, but I am in California.What is considered to be a parent or guardian?
No. Only your parents, or guardian if appointed (you would know if they were) can approve such action until you turn 18. An 18 year-old friend who is not a legal guardian has no legal status to sign such a form.What is considered to be a parent or guardian?
well a parent is someone who gave birth to you and guardian is step parent or a person who adopted you or if your parents passed away they become your legal guardian

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