Harry/Luke has (or had) real parents, but was reared by other family members. Tom Riddle did have a known father and mother, so thats a difference with Anakin Skywalker. (Not that I believed his mothers story about he was just born.) Sure, but in Star Wars the bad guy's own son was the one who 'saved' him after he'd become lost.
Did the HP bad guy knock up Harry's momma?