The Bicentennial Man
Asimov, Isaac. "The Bicentennial Man." Stellar Feb. 1976. Coll. The Bicentennial Man and Other Stories, q.v. under Anthologies and Collections. Rpt. Stellar Science Fiction 2. Judy-Lynn del Rey, ed. New York: Ballantine, 1976.
A robot makes himself into a human being.
Discussed in The Mechanical God by Robert Reilly, "How Machines Become Human: Process and Attribute."