"Recent research provides a potentially urgent reason to ask this question. It shows that pain may leave a lasting, even lifelong, imprint on the developing nervous system. For adults, pain is usually a passing sensation, to be waited out or medicated away. Infants, and perhaps fetuses, may do something different with pain: some research suggests they take it into their bodies, making it part of their fast-branching neural networks, part of their flesh and blood. Anna Taddio, a pain specialist at the Hospital for Sick Children in Toronto, noticed more than a decade ago that the male infants she treated seemed more sensitive to pain than their female counterparts. This discrepancy, she reasoned, could be due to sex hormones, to anatomical differences — or to a painful event experienced by many boys: circumcision. In a study of 87 baby boys, Taddio found that those who had been circumcised soon after birth reacted more strongly and cried for longer than uncircumcised boys when they received a vaccination shot four to six months later. Among the circumcised boys, those who had received an analgesic cream at the time of the surgery cried less while getting the immunization than those circumcised without pain relief. Taddio concluded that a single painful event could produce effects lasting for months, and perhaps much longer. “When we do something to a baby that is not an expected part of its normal development, especially at a very early stage, we may actually change the way the nervous system is wired,” she says. Early encounters with pain may alter the threshold at which pain is felt later on, making a child hypersensitive to pain — or, alternatively, dangerously indifferent to it. Lasting effects might also include emotional and behavioral problems like anxiety and depression, even learning disabilities (though these findings are far more tentative). Do such long-term effects apply to fetuses? They may well, especially since pain experienced in the womb would be even more anomalous than pain encountered soon after birth. Moreover, the ability to feel pain may not need to be present in order for “noxious stimulation” — like a surgeon’s incision — to do harm to the fetal nervous system. This possibility has led some to venture an early end to the debate over fetal pain. Marc Van de Velde, an anesthesiologist and pain expert at University Hospitals Gasthuisberg in Leuven, Belgium, says: “We know that the fetus experiences a stress reaction, and we know that this stress reaction may have long-term consequences — so we need to treat the reaction as well as we can. Whether or not we call it pain is, to me, irrelevant.”"