Final answer:
The birthday rule indicates that the parent whose birthday comes first in the calendar year has the primary insurance plan for the child.
Step-by-step explanation:
The birthday rule in health insurance determines which parent's health plan will be the primary insurance for the child when both parents have coverage.
The birthday rule in health insurance determines the primary insurance for a child when both parents have coverage. Contrary to common misconceptions, it is not about the parent's age or the proximity of their birthdays to the child's.
It is not about which parent is older or whose birthday is closer to the child's. Instead, the rule states that the parent whose birthday (month and day, not year) falls earlier in the calendar year holds the primary plan. This means that if the mother's birthday is in February and the father's in June, the mother's plan would be the child's primary insurance. This rule applies regardless of parental roles or gender and is meant to simplify the coordination of benefits between two insurance plans.