The reality of being called "mom" or "dad" means that you're gonna have to bend the truth somewhat. The lies parents tell their kids range from the ridiculous to the sublime. These lies can range from a simple white lie to a real doozy. It's all just a matter of scale. Whatever it takes, right?
If you're a parent, you know that your little darlings may not always be telling you the absolute truth. Yes, it's hard to believe, but kids lie. A lot. Just because you've been lied to by your child doesn't mean that it has to continue. It's you against them when it comes to the truth. You're their parent, so you should win.