This was a large rich cheese, made by the women of the family with a great affectation of secrecy, and was intended for the refreshment of the gossips who were in the house at the “canny minute” of the birth of a child. Called Ken-no because no one was supposed to know of its existence—certainly no male being, not excepting the master of the house. After all had eaten their fill on the auspicious occasion, the rest was divided among the gossips and taken home. The Kenno is supposed to be a relic of the secret rites of the Bona Dea.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894