Final answer:
The genitofemoral nerve allows for the action of the cremaster muscle reflex.
Step-by-step explanation:
The cremaster muscle reflex allows for the movement that allows you to cross your legs. It is controlled by the genitofemoral nerve. The genitofemoral nerve arises from the lumbar plexus and provides sensation to the skin over the genital area and anterior thigh. It also innervates the cremaster muscle, which is responsible for raising and lowering the testicles in males.