I'm not sure what you mean by they prefer males over females. Are you talking about the behavioral tech job? Anyway, as an ED tech we do a lot of vitals, IV's/blood draws, basic patient needs, urinary catheters, general wound care, EKG's, and if the patient is a trauma or code then we do blood control, CPR, or assist with any other procedures that the physician does like chest tubes, central lines, and various others. There is WAAY more to the job than this but these are some of the most common duties.