How to Add a Stepchild to a Health Insurance Plan

Whether a stepchild is eligible for employer-provided health insurance depends on whom the plan includes in family coverage. Employer group health insurance plans do not have to cover stepchildren. As a result, some plans only include biological and legally adopted children, while others cover stepchildren in both marriage and domestic partnership arrangements.

The rules are different if you purchase a health insurance policy through the Health Insurance Marketplace. According to the rules outlined in the Affordable Care Act, if you don't include the child on your tax return as a dependent you can't add the child to your health insurance.

Enrolling an eligible stepchild during the annual open enrollment period is a relatively simple process. Because insurers are required to accept all eligible applicants during open enrollment, adding a stepchild is a simple matter of filling out an application and providing the child's full name, birth date and Social Security number. Coverage will become effective on January 1 of the coming year.

When you get married, a special enrollment period allows you time to change your health coverage. However, when you add an eligible stepchild during a special enrollment period, you'll need to provide supporting documentation along with the insurance application. Depending on the insurer's rules, you must submit the application and supporting information within 30 to 60 days from the time the child becomes eligible. Documentation requirements usually include a marriage certificate and a copy of the child's birth certificate. Coverage will become effective on the first day of the next month.