Pregnant  women who take  acetaminophen   best known as  Tylenol,  might raise the risk that their child will develop behavioral problems such as attention-deficit/hyperactivity disorder ( ADHD ), a new study suggests. Acetaminophen is generally considered safe in pregnancy -- so safe, in fact, that at least two-thirds of women turn to it while expecting, according to the American Academy of Family Physicians. But when pregnant women in Britain used the pain reliever, it appeared to increase the risk of behavior problems cropping up in their children by the time they turned 7, said lead researcher, a lecturer in genetic epidemiology at the University.

Still, the study couldn't prove cause-and-effect, and the researcher believes that women should still take the drug if needed. In the study, taking acetaminophen between 18 and 32 weeks in pregnancy was associated with a 42 percent…