Now you have me wondering too. I'm still inclined to think it was Clarke because he was much more concerned with scientific and technical plausibility.
But now I'll have to dig into it to find out for sure.
I was wrong, not an infrequent occurrence. It was Asimov, as others suggested:
Here's the ChatGPT question and answer:
Which SF author wrote a story in which communication speed over astronomical distances was made faster by sending messages continually instead of waiting for a reply? In the story it was pointed out that this is how women exchange news on the telephone.
ChatGPT said:
The story you're thinking of is “My Son, the Physicist” by Isaac Asimov (1962). In it, a communications engineer struggles with the long delays of radio messages to Pluto (about 12 hours one way). His mother suggests what women do on the telephone: “Just keep talking”—transmit continuously rather than wait for a reply—effectively creating a live conversation despite the latency
en.wikipedia.org+1tvtropes.org+1
.
This clever idea highlights a real aspect of human communication—especially on the phone—where continuous exchange helps bridge delays, and adapts it to an interplanetary scale. So yes, Asimov used that domestic analogy to demonstrate a practical solution to astronomical message delays.
Of course you are quite right about the loo. In my defence I was unable to look at it to check as I'm out of the country on holiday. :-)
I have been remiss in searching for evidence about the Clarke vs Asimov question. Perhaps I'll try delegating it to ChatGPT.
I don't think that it was sexist in a pejorative anti-woman sense, in my (possibly faulty of course) memory it was said approvingly that women had solved a problem that men were struggling with.
But now I'll have to dig into it to find out for sure.