Szeged in 1934 (1993) [pdf]
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I couldn't follow any of the other papers at the conference I was at, so I went for a walk, found a biology conference, and breezed in. An American woman was presenting results of applying a varying magnetic field to beetle larvae, leading them to grow 4x normal size. This kind of work was effectively forbidden in the US at the time, so results could only be presented at foreign conferences.
The official line in the US at the time, and in many parts still, was that the only possible way for EM fields to affect tissue was through heating. That assumption is written into numerous official standards and regulations. Cell phone radiation is still evaluated solely that way, carefully avoiding e.g. modulating the radiation, as would be needed to produce actually meaningful results. The valid experiment is performed on the general public, instead.
Robert Becker (of "The Body Electric") somehow got a free pass, working for the US Veterans Administration. They probably hoped he would discover how to stimulate regeneration of severed body parts. I have never found out who forbade such research or how they enforced it. I can guess the stricture had to do with preventing political interference with building high-tension transmission lines and maybe radars in populated areas, but that doesn't suggest how they enforced it.
Michael Levin has picked up and has extended Becker's work. And made absolutely astonishing YT vids about it.
The Duties of John von Neumann’s Assistant in the 1930s (2020) - https://news.ycombinator.com/item?id=26826261 - April 2021 (60 comments)
The duties of John von Neumann's assistant (1993) - https://news.ycombinator.com/item?id=16411799 - Feb 2018 (66 comments)
I visited Szeged for the Computer Science Logic conference in 2006 and was quite taken with it - including the Stalinist-era university dorm architecture, and of course all of the paprika-industrial legacy.