Fetal pain, its existence, and its implications are debated politically and academically. According to the conclusions of a review published in 2005, ""Evidence regarding the capacity for fetal pain is limited but indicates that fetal perception of pain is unlikely before the third trimester."" However, there may be an emerging consensus among developmental neurobiologists that the establishment of thalamocortical connections"" (at about 26 weeks) is a critical event with regard to fetal perception of pain. Nevertheless, because pain can involve sensory, emotional and cognitive factors, it is ""impossible to know"" when painful experiences may become possible, even if it is known when thalamocortical connections are established.