For the device with an event occurring on 2016/5/1 at 0:55:25, what is the gender of its user?
on 2016/5/1 at 0:55:25 refers to timestamp = '2016-05-01 00:55:25';
SELECT T1.gender FROM gender_age AS T1 INNER JOIN events AS T2 ON T1.device_id = T2.device_id WHERE T2.timestamp = '2016-05-01 00:55:25'