Third-party custody

In some custody situations, it is possible that the child/children will not remain with either of their natural, biological, parents, but instead custody is awarded to a third person. Generally speaking, third-party custody occurs when one of two options occur:
 * The biological parents do not want custody of the child/children.
 * The biological parents are incapable of caring for the child/children.

Voluntary relinquishment
Occasionally, parents will agree to allow an adult (who is not either of the two parents) to raise their child/children. Generally, if either parent changes his/her mind later in the child's life, he/she has the option to seek custody at that point.

Unfit parents
Custody may be awarded to a third adult (who is not either of the two parents) because the parents both seemed unfit to do so. Reasons that the court would retain authority over the child/children and later award custody to a third adult include:
 * Child abuse/neglect.
 * Substance abuse.
 * Deliberate deserting/abandonment of the child/children.
 * Inability to provide an adequate income which is necessary for the raising of a child.

Other forms of custody

 * Alternating custody is an arrangement whereby the child/children live for an extended period of time with one parent, and then for a similar amount of time with the other parent. While the child/children are with the parent, that parent retains sole authority over the child/children.
 * Bird's nest custody is an arrangement whereby the parents go back and forth from a residence in which the child/children reside, placing the burden of upheaval and movement on the parents rather than the child/children.
 * Joint custody is an arrangement whereby both parents have legal custody and/or both parents have physical custody.
 * Sole custody is an arrangement whereby only one parent has physical and legal custody of a child.
 * Split custody is an arrangement whereby one parent has full time custody over some children, and the other parent has full custody over the other children.