The Collaborative International Dictionary of English v.0.48:

Parentage \Par"ent*age\ (p[^a]r"ent*[asl]j; 277), n. [Cf. F.
   parentage relationship.]
   Descent from parents or ancestors; parents or ancestors
   considered with respect to their rank or character;
   extraction; birth; as, a man of noble parentage. "Wilt thou
   deny thy parentage?" --Shak.
   [1913 Webster]

         Though men esteem thee low of parentage. --Milton.
   [1913 Webster]

WordNet (r) 3.0 (2006):

parentage
    n 1: the state of being a parent; "to everyone's surprise,
         parenthood reformed the man" [syn: parenthood,
         parentage]
    2: the kinship relation of an offspring to the parents [syn:
       parentage, birth]
    3: the descendants of one individual; "his entire lineage has
       been warriors" [syn: lineage, line, line of descent,
       descent, bloodline, blood line, blood, pedigree,
       ancestry, origin, parentage, stemma, stock]

Moby Thesaurus II by Grady Ward, 1.0:

19 Moby Thesaurus words for "parentage":
   ancestry, birth, bloodline, descent, extraction, family,
   grandfatherhood, grandmotherhood, grandparentage, heritage, line,
   lineage, origin, parenthood, pedigree, progenitorship, roots,
   stock, strain



Bouvier's Law Dictionary, Revised 6th Ed (1856):

PARENTAGE. Kindred. Vide 2 Bouv. Inst. n. 1955; Branch; Line.