What generally happened was this. And Earl, let us say, begat an heir. So far, so good. One can always do with an heir. But then - these Earls never know when to stop - he absent-mindedly, as it were, begat a second son and this time was not any too pleased about the state of affairs. It was difficult to see how to fit him in. But there he was, requiring his calories just the same as if he had been first in succession. It made the Earl feel that he was up against something hard to handle.
(from the Preface to Joy in the Morning, by Sir Pelham Wodehouse)