When kids are growing up...
When kids are growing up, they often test their peers to see how they will react to outrageous questions. For instance: "Do you still beat your little sister?" one kid might ask. This, of course, is a question where a yes or no answer will suffice. If one replies, "NO!" then it is an admission that you have beaten your sister on previous occasions. If one answers, "YES," then it is an admission that you currently abuse your sister.
Perhaps the best answer is to say that the problem cannot be solved. You never beat your sister and do not plan to mistreat her in the future.