If a child lives with a step-parent who has coverage, what happens to the biological parent's insurance?

The correct answer is that the biological parent's insurance functions as secondary coverage when a child lives with a step-parent who has a primary insurance plan. This is due to coordination of benefits rules, which stipulate that the step-parent's insurance is considered primary for dependents living in the household. Therefore, the biological parent's insurance serves to supplement the primary coverage, covering additional costs that the primary insurance does not.

Understanding this arrangement is crucial for ensuring that families maximize their insurance benefits and minimize out-of-pocket expenses. The biological parent's insurance can help cover co-pays, deductibles, or services that may not be fully covered under the step-parent's plan.

The other options suggest different scenarios that don't align with the standard practices of insurance coverage for dependents living in a blended family situation. For instance, claiming that the biological parent's insurance is primary contradicts the established norms regarding the hierarchy of insurance plans. Meanwhile, suggesting it is not applicable overlooks the fact that secondary coverage can still provide crucial financial support. Lastly, the idea that it can only be primary if there is no other insurance misrepresents the rules, as it is explicitly determined by the living situation and the insurance policy of the step-parent.