That's a great question, and one that I hadn't thought of before. My dad was born in 1944 at the Bronson Memorial Hospital in Renton, WA too, and I'm still trying to track down if there was any merit to his birth certificate that states his father's name, and that his parents were married. Everyone in the family is sure that my grandma never married his blood father, but the birth certificate states they were married. Also, it lists an address for my grandma's residence, that even according to the Renton Historical Museum, was never a valid address in Renton. Odd... Did you ever find out any more about the hospital?