Father-child bonding among Japanese fathers of infants: A municipal-based study at the time of the 4-month child health checkup.

We aimed to clarify the factor structure of a bonding measure among Japanese fathers with infants and the factors associated with the subscales. Among fathers of children attending the 4-month health checkup, the Japanese version of the Mother-to-Infant Bonding Scale had a two-factor structure comprising "anger" and "lack of affection." Anger was associated with fathers' work demands and poor mental condition, and lack of affection with fathers' older age, poor mental condition, and interpersonal problems at home. Paternal parenting support needs to account for not only the fathers themselves, but also interpersonal communication at home and in the work environment.