If a baby is not smiling, it is not necessarily cerebral palsy. In addition to cerebral palsy, there may be language development disorders or hearing impairment if the baby is completely unresponsive to external stimuli. Cerebral palsy is caused by a non-progressive lesion in the brain that leads to persistent motor dysfunction and abnormal posture, and most cranial magnetic examinations will show pathological changes in the brain. In addition, when a baby has autism, he or she may be unresponsive when teased, have indifferent expressions, and have no eye or voice interaction with his or her mother while breastfeeding. Therefore, if your baby is still unable to be teased or giggle at 3 months of age, you should seek medical attention.