BlackJack by Max Brand
A gunfighter is shot dead in the street. However, when spinster Elizabeth Cornish takes his baby to raise and wagers with her brother that blood will not "out"--that Jack's son will not be a murderer--a fascinating story of nature versus nurture emerges.. Terry is raised with all the advantages and taught he is the last descendant of a fine old Virgina family, never knowing he is the son of the well-known killer, Black Jack Hollis. Will Terry's "bad blood" out? How will he feel when he learns his true identity?