"There's now plenty of evidence that Julius Rosenberg's spy network stole important technology for jet fighters, radar, and detonators. But the one thing he and his spies didn't do a very good job of stealing was atomic secrets–the heart of the prosecutors' case. Most historians agree that the Soviets got the most important atomic bomb-making information from Los Alamos scientists Klaus Fuchs and Theodore Hall, who belonged to a different Russian spy ring.
"The Los Alamos informant Julius was accused of recruiting, Ethel's brother David Greenglass, was a machinist, not a scientist. When a copy of the sketch Greenglass said he drew for the Soviets was made public in 1966, nuclear scientists were not impressed."
Anderson Cooper on 60 Minutes talks with Michael and Robert Meeropol, the sons of Ethel and Julius Rosenberg.