A 2005 study by researchers at the University of Edinburgh in Scotland and the Mount Sinai School of Medicine in New York found that babies born to women in the last half of their pregnancies who witnessed the attacks had higher levels of cortisol (a hormone that is an indicator of stress) than expected. Since the babies studied were about a year old, researchers said these high stress levels in the children may have been transferred by the mother to her child in the womb or by shared genetic susceptibility, said Jonathan Seckl, of the University of Edinburgh.