Pretty rare, yep. Something like ... three or four for every thousand births? Sounds about right. Mirror twins even rarer, since they are only a portion of those three or four.

[ He's said that much though, right? "I favor my left. You favor your right." ]

You wouldn't have concluded it, and I didn't think to mention it. Haha. What a pair that makes us. Now I am just wondering what else I haven't thought to say.