What is the gender of the character 'USAF Master Sgt. Epps?'
character 'USAF Master Sgt. Epps' refers to character_name = 'USAF Master Sgt. Epps'
SELECT T2.gender FROM movie_cast AS T1 INNER JOIN gender AS T2 ON T1.gender_id = T2.gender_id WHERE T1.character_name = 'USAF Master Sgt. Epps'