From the first day of life, infants express non-verbal cues, such as facial expressions, vocalization, and body movement, to convey their physical state and needs to their caregivers. Such a stimulation from infants triggers parenting behaviors. To perform sensitive and appropriate parenting behaviors, interpreting the emotional state and needs of infants based on non-verbal cues is important for caregivers. In particular, the development of parenthood-related changes in the brain, body, and mind for mothers and fathers begin during pregnancy and continues after childbirth through repeated contact with the infant. Thus, this study aims to demonstrate the neurophysiological basis of parenting behaviors in humans. We present our recent findings on mothers' perception of changes in facial expressions as a result of parenting experience, the factors that determine individual differences, and the emergence of parental brain development in fathers. Lastly, we discuss the possibility of an integrated understanding of parental development and support for parents and children.