And that's what we mean by two mutually exclusive events. So flipping a coin once we obtain heads and obtaining heads is mutually exclusive to obtaining tails because either one takes place or the other takes place, both of those events in that single coin flip cannot actually take place. And in the same analogous way, having one child also creates two mutually exclusive events. So we can either get a boy and a girl, but not both, because that is a single process. So we either get one or we get the other. So every time we have a child, usually we only produce one child, either a boy or a girl.