When was the phrase If a cat has kittens in the oven it doesn't make them biscuits first used?

It's an expression that's quickly losing its meaning. I've heard of it being used in the other places for similar reasons, but I've only personally heard it here in Maine:

It used to be commonly accepted, and still is in places, that someone who wasn't born here, or even whose parents were not born here, could not be called a Mainer. Another version is simply "if a cat has kittens in an oven, does that make them muffins?"

This was, and in some places still is, a strong sentiment, derived from Maine's long history of settlement and pride in its culture. However, due to the great mobility that is a part of our modern society, every day it is becoming rarer to find (or even imagine) individuals who can say that their family has been in Maine -never mind in a particular small town- for up to 8 or 9 generations.

A newcomer "from away" (often still called a "flatlander," regardless of the topography of their state of origin) might still say they're "from Maine," but anything beyond that was viewed as presumption.