Used to determine primary and secondary coverage for children. The word "birthday" refers only to the month and day in a calendar year, not the year in which the person was born. If the parents are not separated or divorced, the insurance of the parent whose birthday occurs first in a calendar year is considered the primary insurance while the other parent's benefits are considered the secondary coverage. If the parents have the same birthday, the insurance plan that has covered the parent for the longest time is considered the primary insurance. In situations where the parents are separated or divorced and there is more than one insurance plan covering the child, the benefits are determined in the following order. ** The insurance plan of the parent with legal custody of the child. The plan of the spouse of the parent with legal custody of the child. Last is the plan of the parent who does not have legal custody of the child. ** There can be some discrepancy, depending on a court decree, if there are no specific terms on a court decree (stating only that the parents share joint custody), the benefit determination would be the same as the first bullet above where if the parents are not separated or divorced, the insurance of the parent whose birthday occurs first in a calendar year is considered the primary insurance while the other parent's benefits are considered the secondary coverage.