Why can't cabin crew wear clothes during the medical examination?

Why can't cabin crew wear clothes during the medical examination?

Girls will wear underwear and panties during the flight attendant check-up.

Boys will take off their clothes.

I usually line up in a row, walk a few laps, do push-ups, squat up.

Aviation doctors need to check the body for scars, tattoos, birthmarks and scoliosis.

Girls' private body parts are examined by female aviation doctors.

Also smell for body odor.