That Cell-Phone Cancer Study isn’t Quite As Scary as it Seems by David Z. Morris @FortuneMagazine May 29, 2016, 2:49 PM EST E-mail Tweet Facebook Linkedin Share icons This week, the National Toxicology Program released partial results of a study that found an increased incidence of cancer in male rats exposed to radiation from cell phones. The possibility that cellphones cause cancer has long worried the public, so it’s not surprising that media outlets ran headlines suggesting the study fully confirmed our worst fears. But critics have quickly pointed out that the substance of the study just doesn’t support such big claims. Dr. Aaron Carroll, a professor at the Indiana University School of Medicine, did a close reading of the study, (via Vox) and saw some things that should trigger skepticism. Get Data Sheet, Fortune’s technology newsletter. For a start, while there were slight increases in some types of cancer in male rats in the study, Carroll points out that female rats were treated to the same signals—and there was no increase in their cancer rates. And a statistically significant increased incidence of brain cancer for male rats was only found for CDMA signals, not GSM. That’s surprising because, while real-world GSM phones emit more radiation than CDMA phones, the experimental radiation exposure levels were held constant between parallel groups. And since the main difference between GSM and CDMA is their data standard, there should only be different impacts if DNA could be corrupted by binary code. All that suggests the results could simply be a statistically random variation, especially since, as Carroll points out, even the elevated cancer rates were “well within the historical range.” Another expert called the study “statistically underpowered,” with a sample size too small to eliminate that kind of random variation. There’s no way to refute that explanation until more studies can reproduce this one’s results. For more on health and technology, watch our video. Another result of the study is even more head-scratching: the groups of rats exposed to cell signals lived longer than those not exposed. That doesn’t mean that cell phone radiation will extend your lifespan. But, Carroll writes, it could mean the exposed group simply developed cancer as an inevitable part of aging, while the non-exposed group died before tumors could develop. Carroll is an established skeptic of cell-phone cancer fears, and he has some very solid logic in his corner. In the below video, Carroll explains that cell phones simply don’t emit the sort of radiation that we know damages DNA and causes cancer—that’s high-energy ionizing radiation, from sources like x-rays and gamma rays. Cell phone “radiation” is non-ionizing, low-power radiation, just like radio waves, Wi-Fi, and Bluetooth. Such technologies have become much more prevalent since the 1980s, but according to the National Cancer Institute, cancer rates have actually declined slightly over that period.