Final answer:
The external genitalia in both males and females are primarily innervated by the pudendal nerve, a large somatic nerve originating from the sacral plexus in the lower spine. The pudendal nerve branches out to supply various sensory and motor fibers to the external genitalia, perineum.
Step-by-step explanation:
The nerves that innervate the external genitalia include the pudendal nerve, hypogastric nerve, and pelvic nerve. The pudendal nerve arises from the sacral micturition center and provides voluntary control of the external urethral sphincter. The hypogastric and pelvic nerves play a role in the control of urination and detrusor muscle contraction in the bladder.