Bumbo seat they can have a negative effect on children’s posture other inconsistencies bad for baby’s spine and gross motor development bad for baby’s spine and gross motor development Chicago Tribune, baby may not benefit studies out there Colleen Harper, P.T. told the Chicago Tribune, other inconsistencies Therapists see no developmental benefits from seats bad for baby’s spine and gross motor development other inconsistencies opinion of physical therapists other inconsistencies bad for baby’s spine and gross motor development