Child custody rights are determined by a family court judge based on the best interests of the child. Child Protective Services has some influence in these decisions if there is a history of abuse or neglect. Sole child custody rights can be granted to either parent but are usually given to the mother. This is based on several factors including society's expected role for mothers and on the fact that fathers rarely seek custody. Child custody rights can be modified or terminated by the court if sufficient cause can be shown. Parents who wish to dispute custody arrangements often hire an attorney to help them since this process can be complicated. In some cases, joint custody may be granted but one parent must still pay child support. If this parent fails to pay, this does not affect his or her child custody rights. In the event that a child is adopted by a step parent and the birth parent signs away parental rights, child custody rights are usually terminated.