Expectant mums who use mobile phones could cause health issues such as ADHD and anxiety in their children, according to a new study.
However, the research has been slammed by British scientists.
The team at Yale University tested the effects of exposure to radiation from mobile phones on pregnant mice. But scientists from the University College London argued that the findings were unjustified and that mice and humans do not make comparable subjects.
The researchers found the radiation exposure affected the brain development of the newborn mice, potentially leading to increased activity, anxiety and impaired memory, concluding that this could have a negative effect on babies in womb.
The researchers measured the brain electrical activity of adult mice that were exposed to radiation as foetuses and conducted a series of tests to identify factors associated with ADHD, such as impairments in memory, hyperactivity, anxiety and fear.
The mice that had been exposed to the radiation were found to have increased anxiety and activity and reduced memory capacity.
However, the researchers pointed out the amount of radiation the unborn mice were exposed to was proportionally far higher than an unborn baby would get as the whole bodies of the mice were exposed while a pregnant woman would usually hold her phone a metre from uterus.
The findings, published in journal Scientific Reports, suggested a link between the rising number of ADHD cases and the use of mobile phones.
Senior author Professor Hugh Taylor said: "We have shown that behavioural problems in mice that resemble ADHD are caused by mobile phone exposure in the womb.
"The rise in behavioural disorders in human children may be in part due to foetal cellular telephone irradiation exposure."
However, Eric Taylor, Emeritus Professor of Child & Adolescent Psychiatry, Institute of Psychiatry, King's College London, argues that mice and humans do not make comparable subjects for such a study and that it is unlikely mobile phones are responsible for rising ADHD rates.
He said: "This paper does not show any link between radiofrequency exposure and ADHD.
"The rate of ADHD problems has been steady for more than 20 years, any increase is due to greater recognition, so mobile phones are an unlikely cause.
"Taking animal studies and extrapolating directly to humans requires much more care.
"The exposure of the animals was very great, and the researchers' tests of animal memory should not be directly equated to human attention; different species can react differently."
The study authors acknowledged that further testing would be necessary to establish safe exposure limits for human babies, writing in Scientific Reports:
"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."
Professor Malcolm Sperrin, Director of Medical Physics and Clinical Engineering, Royal Berkshire Hospital, said: "This paper presents work from a highly respected organisation and does bring additional insight into how electromagnetic radiation may affect tissue and its development during gestation.
"However, the authors repeatedly state that any correlation between the effects on mice during the study and predicted effects on humans are too tenuous to be reasonably claimed.
"Great caution must be given not to stretch the data too far until more work is done to move toward human equivalent studies," he said.