"Evidence of harm from cell phones continues to emerge: First there was the possible cancer link, and now there's suggestion that those little hand-held devices may affect children's behavior. Children who had exposure to cell phones both in the womb and after birth, up to age 7 had a higher likelihood of behavioral problems than those who had no exposure, researchers said in a new study in the Journal of Epidemiology & Community Health. The behavioral problems include hyperactivity and attention and social issues. The association between cell phone exposure is not terribly strong, Kheifets said. Also, the authors do not yet know the mechanism behind the connection between cell phones and behavioral problems. One theory is that cell phone use may lead to excess secretion of the hormone melatonin, which can affect the mother's metabolism and may influence the development of the fetus's brain. But this is just a speculation, Kheifets said. There is also no way to know whether the mothers were telling the truth about the amount of cell phone time they had. It's impossible to tell from this research whether cell phone exposure really causes behavioral problems. Still, given how many people use cell phones in the world, it's important to keep an eye on possible harms, Kheifets said. She recommends limiting exposure to radiation through the use of hands-free devices. (Behavioral Problems)"
First off, I'd like to say that the connection between the two things is not very strong and more testing and research needs to be done to prove that cell phones cause behavioral problems in children. Second, if you are sincerely worried about your child developing behavioral problems from cell phones; don't use one as often as you normally would when you are pregnant and don't let your child have a cell phone till middle school. A child doesn't need a cell phone in elementary school anyway. As for this study, I feel it will be really hard for anyone to prove that cell phones have a direct effect on the behavior of a child due to the other variables that also cause behavior problems, like the way the child is brought up (nurture) and the genetic make-up of the child which determines personality (nature). However, like I said earlier if you are sincerely worried for your children take the necessary precautions to keep them safe.