In most juridictions there is no need for the parents to be married, and only paternity and/or maternity (filiation) need to be demonstrated for a child support obligation to be found by a competent court. Child support may also operate through the principle of estoppel where a defacto parent that is in loco parentis for a sufficient time to establish a permanent parental relationshp with the child or children.
Child support is based on the policy that the parents are obliged to pay for the support of their children, even when the children are not living with both biological parents and even when only one parent is given the role of caregiver for the child or children. This occurs when the other parent is not given legal or physical custody. In such cases the obligation to care for the child or participate in major decisions in the child's upbringing may only fulfilled financially, though courts usually grant visitation to non-custodial parents.
In some jurisdictions the privilege of visitation (or access) is tied to child support, if the custodial parent refuses to allow the non-custodial parent to visit with the child the non-custodial parent can petition the court to temporarily stop support payments. However, some jurisdictions view this as punishing the child, not the parent and in such cases the court may order additional visitation to the non-custodial parent. Visitation, is a limited form of custody.
Child support laws vary around the world. Some jurisdictions sort the arrangements out directly between the parents. Others involve the state, often collecting child support payments as an extra income tax. In the United States some non-custodial parents see that there is no accountablity on the part of the custodial parent regarding how child support payments are spent, they accuse the custodial parent of spending the support payments on non-child related expenses. The only recourse is for the non-custodial parent to petition the court for a change of custody, which is often a very difficult change to achieve.
Because of the high levels of payments sometimes demanded, the avoidance of child support payments is common. Many non-custodial parents who have been subject to acrimonious divorces often see these payments as unfair and excessive. Some custodial parents who have been the victim in abusive relationships view the avoidance of child support payments by the other parent as another way of perpetuating the abuse. Those who avoid their child support obligations are often termed dead-beat parents as a result.
In the United States many states are now passing laws suspending an individual's licenses (including driver's licenses) if they have a significant arrearage in support payments.