English: Real-time video demonstration of the cremasteric muscle reflex in an adult male. The subject is a healthy 27-year-old Caucasian male whose genitals are in a flaccid, nonaroused state. To demonstrate the reflex, the subject lightly strokes his right and left inner thighs, first in downward and then in upward motions. After each stroke, the reflex can be observed as an immediate elevation of the testicle on that side (caused by a contraction of the accompanying cremaster muscle). The left muscle is contracted (and the left testicle elevated) three times, and the right muscle is contracted (and the right testicle elevated) twice. The unilateral effects of the cremasteric reflex can be compared with the bilateral effect of the arousal process and the retraction of the testicles into the inguinal canals.