Fridwulfa was a giantess. She was the mother of Hagrid, but abandoned her human family around 1931. She had another child, a son named Grawp, by another giant (OP20).
Abandoned her human family when Hagrid was 3 years old. (GF23)
In his song "Book Eight", Hank Green raises a point about Hagrid's parents: "And I know I wanna hear the one/ About Hagrid's dad and Hagrid's mum./ I really do think that that's nearly impossible./ And I think there's probably a good story there." (source: YouTube)