Re:Human reproductive cloning: The curious incident of the d...
by philipkglass on Wednesday February 26, 2020 @04:50PM
(#22427742)
The Manhattan Project started in 1942, was penetrated by Soviet spies no later than 1943 (Klaus Fuchs), and was known to the whole world by 1945. It's not a great example of extended secret-keeping.
Another data point: The Manhattan Project. It was large, involved a ton of people, and still managed to keep a lot of secrecy around itself for some time.
Likewise, the Guatemala syphilis experiments: https://en.wikipedia.org/wiki/Guatemala_syphilis_experiments