There's something about cell phones that make medical alarm bells ring. Do you remember the reports of cell phones causing cancer? How about the dangers of exploding cell phone batteries? Now there's a new risk factor -- researchers are saying that cell phone usage during pregnancy can cause hyperactivity and emotional or behavioral issues in children.

Over 13,000 mothers in Denmark were surveyed -- some didn't use a cell phone at all, others used one sporadically, and a third group used their cells often during pregnancy. Their results indicate that using a cell phone as little as two to three times a day during pregnancy can cause health issues -- hyperactivity, conduct issues, emotional issues, or difficult with relationships -- for the children. What's more, if the children used cell phones themselves before age 7 they were 80% more likely to have behavioral issues.