male genitals vs family jewels

male genitals and family jewels both are nouns.

Word	Noun	Adjective	Verb	Adverb
male genitals	Yes	No	No	No
family jewels	Yes	No	No	No

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

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

male genitals (noun)	family jewels (noun)
external male sex organs	external male sex organs