Under the Nevada birthday rule for health insurance, when a child is covered under both parents’ health plans and the parents are married or living together, the plan belonging to the parent whose birthday falls earlier in the calendar year pays first. Only the month and day count. The birth year is irrelevant, so the older parent is not automatically primary.
Nevada follows the National Association of Insurance Commissioners (NAIC) Coordination of Benefits Model Regulation, which most states have adopted in some form to keep carriers from fighting over which one pays first.1National Association of Insurance Commissioners. Coordination of Benefits Model Regulation The state’s coordination of benefits framework is grounded in NRS 689A.230 for individual health policies and parallels the NAIC model.2Nevada Legislature. Nevada Code NRS 689A.230 – Coordination of Benefits: All Coverages
How the Rule Picks the Primary Plan
If one parent was born on February 8 and the other on September 22, the February parent’s plan is primary regardless of who is older, who earns more, or who has been at their job longer. The model regulation explicitly defines “birthday” as the month and day only, excluding the year of birth.1National Association of Insurance Commissioners. Coordination of Benefits Model Regulation
The primary plan then processes each claim as though it were the child’s only coverage. It applies its normal deductible, copay, and coinsurance. Whatever balance is left after the primary plan pays goes to the secondary plan for further reimbursement.
What Happens When Both Parents Share a Birthday
When both parents were born on the same month and day, the calendar comparison yields no winner. The NAIC model regulation resolves this by designating the plan that has covered the parent for the longest continuous period as primary.1National Association of Insurance Commissioners. Coordination of Benefits Model Regulation Duration is measured from the parent’s original enrollment date on that specific plan. If one parent has been on their employer’s plan since 2018 and the other enrolled in 2023, the 2018 plan takes the lead.
If both plans started on the same date and neither insurer can establish priority, the plans typically split allowable expenses equally or fall back on additional tiebreaker provisions written into their own contracts.
Divorced or Separated Parents
The birthday rule only applies when parents are married or living together. If you’re divorced or legally separated, any court order addressing the child’s health coverage controls, and the standard priority order looks like this:
- The plan of the parent a divorce decree or custody order names as responsible for the child’s medical expenses pays first.
- If no court order addresses insurance, the plan of the parent with physical custody pays first.
- Next in line is the plan of the custodial parent’s new spouse, if any.
- The plan of the non-custodial parent is last.
Insurance adjusters must follow this hierarchy regardless of which parent has the earlier birthday. Give both insurers a copy of the relevant court order so claims route to the correct primary plan from day one. Without that documentation, insurers often default to the birthday rule, and when the other carrier does the same, the family gets stuck in the middle.
Qualified Medical Child Support Orders
If a parent’s employer offers a group health plan, federal law adds another enforcement tool: the Qualified Medical Child Support Order (QMCSO). A QMCSO is a court judgment or administrative order that requires a group health plan to cover a participant’s child, even if the employee hasn’t enrolled the child voluntarily.3Office of the Law Revision Counsel. 29 USC 1169 – Additional Standards for Group Health Plans It can come from a court or from a state child support enforcement agency.
To qualify, the order must include the names and mailing addresses of the covered parent and each child, a description of the type of coverage required, and the time period the order covers.3Office of the Law Revision Counsel. 29 USC 1169 – Additional Standards for Group Health Plans The order cannot force a plan to offer benefits it doesn’t otherwise provide. Once the plan receives a valid QMCSO, it must treat the child as a covered dependent, and that assignment can establish primary responsibility by operation of the court order.
How the Secondary Plan Actually Pays
The secondary plan does not simply cover whatever the primary plan left behind. Nevada’s coordination of benefits statute caps combined payments from both plans at the total allowable expense for the service.2Nevada Legislature. Nevada Code NRS 689A.230 – Coordination of Benefits: All Coverages Dual coverage can meaningfully reduce out-of-pocket costs, but it won’t generate a profit.
Secondary plans generally use one of two methods. Under a non-duplication approach, the secondary plan looks at what it would have paid if it had been primary; if the primary plan already paid that much or more, the secondary pays nothing. Under a maintenance of benefits approach, the secondary plan subtracts whatever the primary plan paid from the total bill and then applies its own deductible and coinsurance to the remainder. Maintenance of benefits almost always leaves the family with some remaining cost-sharing, and non-duplication can leave them with more. Ask your secondary carrier which method applies so you can set realistic expectations about the final bill.
Self-Funded Employer Plans Can Ignore the Rule
Not every employer health plan has to follow Nevada’s coordination of benefits rules. Large employers often self-fund their health plans, meaning the employer pays claims directly rather than buying insurance from a carrier. Those plans are regulated under the federal Employee Retirement Income Security Act (ERISA), not state insurance law.
ERISA’s preemption clause broadly overrides state laws that relate to employee benefit plans.4Office of the Law Revision Counsel. 29 USC 1144 – Other Laws Although ERISA preserves state authority to regulate the business of insurance, self-funded plans are excluded from being treated as insurance companies under state law. In practice, a self-funded employer plan can write its own coordination rules and may not apply the birthday rule at all.
If one parent’s coverage is self-funded and the other’s is a traditional insured plan, the two carriers may apply different coordination rules. Federal regulations generally direct each plan to follow its own rules first; if the conflict persists, the plans typically pay in the order that treats the child as primary under the plan without a coordination provision, or they split expenses. Before any significant treatment, call both plan administrators and ask which plan considers itself primary. Your Summary Plan Description will tell you whether the plan is self-funded or fully insured.
Adult Children Under 26 With Their Own Coverage
The Affordable Care Act requires plans that offer dependent coverage to keep adult children enrolled until they turn 26, regardless of whether the child has access to their own employer plan.5U.S. Department of Labor. Young Adults and the Affordable Care Act: Protecting Young Adults and Eliminating Burdens on Businesses and Families FAQs This creates a common dual-coverage scenario: a 24-year-old working full time with their own employer plan who is also still on a parent’s plan.
The birthday rule does not apply here, because the adult child is not a dependent covered under two parents’ plans. The person’s own plan as an employee is primary, and the parent’s plan where they’re listed as a dependent is secondary. Families often don’t realize this and submit to the parent’s plan first, which triggers a denial.
Preventing and Fixing Wrong-Plan Denials
Sending a claim to the wrong plan as primary is one of the most common dual-coverage billing mistakes. An insurer that receives a claim it believes belongs to the other carrier first will typically deny it outright rather than process it as secondary. The denial does not mean the service isn’t covered. It means the billing order was wrong.
Fixing it requires resubmitting to the correct primary insurer, waiting for that Explanation of Benefits (EOB), and then sending the remaining balance to the secondary plan. The process can add weeks or months to payment, and some providers will send the balance to collections if the delay drags. A few habits head this off:
- Call both insurers before treatment, verify which plan is primary for your child, and get a reference number for the call.
- Give the doctor’s office or hospital both insurance cards and tell them which is primary.
- Keep both parents’ birth dates on file with both plans. If the dates are missing or wrong, the determination stalls.
- Save every EOB. The secondary plan needs the primary plan’s EOB to calculate its share, and missing paperwork is the top reason secondary claims sit unprocessed.
If both insurers deny a claim by pointing at each other, contact the Nevada Division of Insurance. The division can step in to resolve coordination disputes between carriers operating in the state.