Her infant was a boy too.

Now, would it be possible for her to change them?
Though he was soon satisfied that he had dismissed the idea as romantic and unlikely--though possible, there was no denying--he could not help pursuing it so far as to entertain within himself a picture of what his condition would be, if he should discover such an imposture when he was grown old.

Whether a man so situated would be able to pluck away the result of so many years of usage, confidence, and belief, from the impostor, and endow a stranger with it?
But it was idle speculating thus.

It couldn't happen.

In a moment afterwards he determined that it could, but that such women were constantly observed, and had no opportunity given them for the accomplishment of such a design, even when they were so wicked as to entertain it.