A very polite with a stern stare... "excuse me could you repeat that?" warns off all but the most serious offenders.
"Your comment makes me uncomfortable, can we please return to the focus of YOUR care?"... said in the nicest, calm demeanor.
"I am a very well skilled registered nurse... if you have concerns about my capabilities of caring for you I can call my supervisor to discuss my credentials with you.....?"
"I thank you for your comments, but do not mistake my youthful look for lack of experience..."
And for those, god love 'em that keep it up... "I don't find your comments in jest, and I'm concerned about your lack of trust in our nurse/patient relationship... do we need to make an adjustment in nurse assignments to better suit your needs?"
TAKE NO GARBAGE.. but immediately call them on it to force them to be uncomfortable to act as they should ... in an appropriate manner. I will never tolerate that crap. I am NOT the subject of their amusement. I am the nurse