male parent vs daddy

male parent and daddy both are nouns.

Word	Noun	Adjective	Verb	Adverb
male parent	Yes	No	No	No
daddy	Yes	No	No	No

As nouns, daddy is a hyponym of male parent; that is, daddy is a word with a more specific, narrower meaning than male parent:

Other hyponyms of male parent include dad, dada, pa, papa, pappa, pop, father-in-law, old man, pater.

male parent (noun)	daddy (noun)
a male parent (also used as a term of address to your father)	an informal term for a father; probably derived from baby talk