In a recent Takimag column, John Derbyshire describes reading Emile Zola's Nana, (on the advice of Tom Wolfe)

Zola describes Nana as having been “born from four or five generations of drunkards.” Sniffs editor Luc Sante in the 2006 Barnes & Noble Classics edition: “The genetic notions advanced here have long been discredited, although we know that behavior is often handed down through the generation by example.”

Uh-huh. I’m starting to favor a Constitutional Amendment to the effect that anyone saying in print or pixels that such-and-such a notion has been “discredited” should be obliged to tell us by whom the discrediting was done, when, where, with what methodology, and the specific informed criticism that countered it.

The hereditary nature of alcoholism is about as well established, in a formulation I first heard from Derbyshire himself in the year  2000, as the orbit of the moon.