The expression, while humorous, underscores the fact that people will sometimes throw irrelevant questions or comments into a discussion thereby changing the original focus of what was already being discussed (see the video included below).
Back in 1984, while watching Star Trek III: The Search for Spock, I heard Scotty exclaim, “Aye, and if my grandmother had wheels, she’d be a wagon.” It was an interesting take — this counterfactual thinking — on what was allegedly an everyday-life situation for Scotty! But where did this expression come from and where would Idiomation find the earliest published version?
Just 6 years before the movie’s release, the New York Times ran an article on February 27, 1978 entitled “Albany’s patronage Roots Hidden By Change In Law” written by Steven R. Weisman. He reported:
[Assemblyman Stanley Fink, the majority leader] asked her a question and she replied with a phrase she translated as, “If my grandmother had wheels, I would have been a bus.”
Nearly a decade before that, The Pittsburg Press ran an article on August 26, 1970 written by Wauhillau La Hay entitled “Hormone Theory Drawn Into Women’s Lib Debate.” Here readers were treated to the following:
Dr. Ramey noted that “Dr. Berman says genetics is destiny. I think what he’s trying to say is that human beings with ovaries should not enter the White House as president. That if I did not have a certain XY (chromosomes) in my blood, I’d go th the men’s room, not the ladies’ room. That’s like saying if my grandmother had wheels, she would be a station wagon,” Dr. Ramey declared.
She argued against the position that women are inferior because they suffer from discomfort during menstrual periods, saying “Pioneer women crossing the plains didn’t take time out for cramps, did they?” Her audience cheered.
The English saying is a direct translation of the Spanish: “Si mi abuela tuviera ruedas seria una bicicleta” (If my grandmother had wheels, she’d be a bicycle.).
However, the sense of the phrase is found in the older French expression: “Avec des si et des mais, on mettrait Paris en bouteille” (With ifs and buts, we would bottle Paris.)
The earliest published variation of the expression about grandmother having wheels that Idiomation could find is in the book, Jiddische Sprichwörter , written by Ignaz Bernstein and B.W. Segel, published in Frankfurt, Germany in 1908.
This video is a perfect example of the use of the idiom.
Historically Speaking 