A little gem of a fable by Mr. Ambrose Bierce:
The Overlooked Factor
A Man that owned a fine Dog, and by a careful selection of its mate had bred a number of animals but a little lower than the angels, fell in love with his washerwoman, married her, and reared a family of dolts.
"Alas!" he exclaimed, contemplating the melancholy result, "had I but chosen a mate for myself with half the care that I did for my Dog I should now be a proud and happy father."
"I'm not so sure of that," said the Dog, overhearing the lament. "There's a difference, certainly, between your whelps and mine, but I venture to flatter myself that it is not due altogether to the mothers. You and I are not entirely alike ourselves."