Given the task definition and input, reply with output. Given a scientific passage and an answer, generate a question for the given answer.

Passage: Red blood cells carry proteins called antigens on their surface. People may vary in the exact antigens their red blood cells carry. The specific proteins are controlled by the genes they inherit from their parents. The particular antigens you inherit determine your blood type. Answer: antigens
What are the specfic types of proteins that determine your blood type called?