parentage vs blood line

parentage and blood line both are nouns.

Word	Noun	Adjective	Verb	Adverb
parentage	Yes	No	No	No
blood line	Yes	No	No	No

As nouns, parentage and blood line are synonyms defined as:

Other synonyms of parentage include ancestry, blood, bloodline, descent, line, line of descent, lineage, origin, pedigree, stemma, stock.

parentage (noun)	blood line (noun)
the hereditary derivation of an individual	the hereditary derivation of an individual
the kinship relation of an offspring to the parents
the state of being a parent