Question: What is the average height of male athletes playing basketball sport?
SQL: SELECT AVG(T5.height) FROM sport AS T1 INNER JOIN event AS T2 ON T1.id = T2.sport_id INNER JOIN competitor_event AS T3 ON T2.id = T3.event_id INNER JOIN games_competitor AS T4 ON T3.competitor_id = T4.id INNER JOIN person AS T5 ON T4.person_id = T5.id WHERE T1.sport_name = 'Basketball' AND T5.gender = 'M'