David Haglund in Slate (via The Brooklyn Institute for Social Research):
Quote Investigator is a terrific website that examines the provenance of popular quotations, which, as you may have noticed, frequently get misattributed online. On Monday, the site’s proprietor, Garson O’Toole, looked into a six-word fiction supposedly written by Ernest Hemingway: “For sale: baby shoes, never worn.”
Hemingway’s authorship of the classified ad-inspired short-short story is frequently described as a “literary legend,” which, to be fair, is a perfectly accurate way of putting it. Snopes looked into the legend a few years ago, and decided that its basis in fact was “undetermined.” But after reading O’Toole’s more thorough investigation, it’s very hard to believe that Hemingway had anything to do with the tale.
Ernest Hemingway died in 1961, and the earliest published evidence known to QI connecting him to this tale appeared in 1991. The author Peter Miller included a version of the anecdote in his book Get Published! Get Produced!: A Literary Agent’s Tips on How to Sell Your Writing. Miller stated that he was told the tale by a “well-established newspaper syndicator” circa 1974.
The case for Hemingway does not get stronger from there. As O’Toole documents, the precursor to the story seems to be a 1921 newspaper column by Roy K. Moulton, who “printed a brief note that he attributed to someone named Jerry.”
There was an ad in the Brooklyn “Home Talk” which read, “Baby carriage for sale, never used.” Wouldn’t that make a wonderful plot for the movies?
That note was reprinted in multiple newspapers.