Nurse did not know that his "sister" was in fact his mother until he was in his 50s: his application for a green card for US residency while president of Rockefeller University was, to his surprise, rejected, despite his being a Nobel Prize winner, president of a university and a knight; this was because he had submitted a short-form UK birth certificate which did not name his parents. When he applied for a full birth certificate he discovered the truth, to his astonishment.