‘Courts have generally held that interference by a child’s custodian with the visitation rights of the noncustodial parent constitutes a ground for modification of a custody order… reasoning that one who willfully disobeys a valid court order concerning visitation rights, and shows such little respect for constituted authority, can hardly lay claim to being the best custodian for a child.’

For example: ‘Court did not err in changing physical custody from mother to father where court found that mother repeatedly, intentionally, and unjustifiably denied and interfered with father’s visitation rights on numerous occasions and that she regularly violated court orders regarding visitation, where court further found that mother repeatedly filed numerous, unfounded reports of abuse against father and was convicted on two counts of filing false reports, where court concluded that mother’s behavior and actions were not in best interests of child, and where court observed that several investigations associated with mother’s false reports had been traumatic for child. Beyer v Tranelli-Ashe (1993, App Div, 4th Dept) 600 NYS2d 598.’ However, in other cases, ‘custody should not be changed when to do so would punish a parent for past behavior and where there is no proof of a detrimental effect on the child or children…’

Thus the father is usually burdened with the proof of showing detrimental effects on his children — even when the mother violates custody orders. Yet there seems to be an implicit doctrine that ‘if either parent should attempt to influence the child to disrepect or to lose her affection for the other, such a parent would forfeit all claim to the child’s custody.’ An extremely detailed case law discussion can be found