They have asserted that the study actually indicates that cell phone use more than doubles the risk of brain tumours in children and adolescents.
The concerns come from the Environmental Health Trust, a group whose stated mission is to promote awareness of environmental issues they think can lead to cancer.
In July 2011, the Journal of the National Cancer Institute published the first study on cell phone use and risk of brain tumours in kids and adolescents, which was conducted by researchers at the Swiss Tropical and Public Health Institute.
The scientists interviewed children and teens in Norway, Denmark, Switzerland and Sweden about their cell phone use and also collected cell phone records for a portion of them. Of the children studied, 350 had been diagnosed with and 650 of them were healthy.
The July paper concluded that the data indicated no link between cell phone use and brain tumours and "argues against a causal association" between the two.
However, in a recently published letter, the Environmental Health Trust said the interpretation of the study's results was flawed and contained several statistical errors.
Lloyd Morgan, a senior research fellow at the Environmental Health Trust and one of the authors of the letter, called the study "sloppy" and insisted that the information reported in the original study in reality show that children who used cell phones had a 115 percent increased risk of brain tumours over those who did not.
"There's every indication that this study actually found that children have a doubled risk of brain cancer," ABC News quoted Morgan as saying.
"For them to just state that we don't think there's a problem is, for me, quite mystifying."
The authors of the original study did mention about some limitations of their work, including that a relatively small number of children were studied. They also said that they could not "rule out the possibility that mobile phones confer a small increase in risk."