male genital organ vs crotch

male genital organ and crotch both are nouns.

Word	Noun	Adjective	Verb	Adverb
male genital organ	Yes	No	No	No
crotch	Yes	No	No	No

As nouns, crotch is a hypernym of male genital organ; that is, crotch is a word with a broader meaning than male genital organ:

Other hypernyms of male genital organ include genital organ, genitalia, genitals, private parts, privates.

male genital organ (noun)	crotch (noun)
external male sex organs	the angle formed by the inner sides of the legs where they join the human trunk
	external sex organ
	the region of the angle formed by the junction of two branches