Can a Parent Take a Child Out of State to Live Without the Other Parent's Permission? notes that parental kidnapping laws vary from state to state and depend on factors such as whether the parents are married and whether the children are involved in a court case like a custody battle. Parents who want to relocate a child should always consult with an attorney before making any commitments on leaving the state, especially if the couple is going through or has been through a divorce.

In most states, the other spouse must give permission for the child to be relocated. If the child is part of a court case, the judge may have to give permission. Even temporarily removing the child from the state can be illegal if he is part of a court case for custody or divorce proceedings, notes

According to Wikipedia, parental kidnapping, also known as parental child abduction, is defined as child abduction by a parent. This parent may be relocating the child or refusing to return the child after an access visit. A parent may also flee with the child to prevent such visits or if he fears domestic violence or abuse is occurring. In instances where one spouse gives permission for another to relocate a child to another state, a person should always get a notarized signature from the spouse to prevent future parental kidnapping accusations.