A man lights up a cigarette in Jakarta on Sept. 29, 2010 (Adek Berry/AFP/Getty Images)

For scientists concerned about radiation from gadgets like cellphones, microwaves, and Wi-Fi, the doubt cast on studies showing their harm to humans is similar to studies done on tobacco in the early 20th century.

The science showing a positive link between cancer and tobacco was deemed inconclusive and not causal enough to be taken seriously throughout the ’20s, ’30s and ’40s.

But as the number of studies increased and the media started to pick up on its hazard to public health in the 1950s, the correlation gradually became accepted, even by the tobacco industry.

The industry adapted, however, introducing “cleaner” cigarettes with low-tar formulas, and released a propaganda campaign to…