male genital organ vs family jewels

male genital organ and family jewels both are nouns.

Word	Noun	Adjective	Verb	Adverb
male genital organ	Yes	No	No	No
family jewels	Yes	No	No	No

As nouns, male genital organ and family jewels are synonyms defined as:

Other synonyms of male genital organ include male genitalia, male genitals.

male genital organ (noun)	family jewels (noun)
external male sex organs	external male sex organs