The agency I adopted from told me they destroy the records after 16 years. Is that legal? And how do I follow up? He is 18 and wants to know.

Every state requires adoption agencies to keep copies of adoption records forever. If they go out of business the state Department of Social Services (sometimes called the Department for Youth, Family and Children's Services) keeps the records. Please contact the state Department of Social Services so you can find out where these records are. Your son has a right to know the medical, cultural, and social history of his biological family.