"Do you have parents?"
Translation:Hast du Eltern?
When using the informal you "du", there is a different conjugation of the verb. For the verb "haben", this would be "hast." ex: Du hast Eltern. Hast du einen Tisch?
"Haben Sie Eltern" was correct because the formal you "Sie" was used; we know this because of the capitalization of "Sie" in the middle of the sentence. The conjugation for formal you "Sie" is the same as the conjugation for they "sie" (note that this is not capitalized unless it begins the sentence). ex: Haben Sie Zeit? (Do you have time?), "Sie haben einen Hund" (You have a dog.)