Conversation so far:
What was Seattle Slew's heritage?
Seattle Slew was the first foal out of My Charmer, a stakes-winning daughter of the otherwise obscure sire Poker.
Did Seattle Slew show signs of his greatness early on?
Seattle Slew was not considered particularly attractive as a foal, leading some to say he looked like a mule.
When was Seattle Slew's first race?
He finally made his first start in a six-furlong maiden race on September 20, 1976.

Question: Who were his parents?
Self-contained rewrite: Who were Seattle Slew's parents?