(1) Whether your parents have married after you were born ? (2) Did your parents get married after you were born ? (3) Have your parents married after you were born ? Which one is more appropriate sentence ?
Definitely 2. (1) is a clause, not a sentence.(3) means you wonder if his/her parents have beenmarried. But actually they did, and you just wantto know the timing of their marriage.So the simple past tense is the best answer.