But the Environmental Health Trust, a charitable organization whose mission is to educate the public about health risks in the environment, says the evidence from multiple studies shows there is reason to be concerned about the effects of cell phones.
They urge people to keep phones away from their head and their body when they are in standby mode and to avoid using them when the signal is weak. The group is also calling for more long-term research exploring the issue further.
And almost every phone manufacturer includes warnings in packaging urging users to take precautions.
The authors of the current study hope their findings will contribute to the understanding of how childhood behavior problems develop.
"The rise in behavioral disorders in developed countries may be, at least in part, due to a contribution from fetal cellular telephone radiation exposure," they wrote. "Further testing is warranted in humans and non-human primates to determine if the risks are similar and to establish safe exposure limits during pregnancy."