Three age milestones are in play when it comes to your responsibility for your own health insurance. When you turn 26, insurers no longer have to include you in a family policy. At 18, you're legally an adult. And 14 is the earliest age of emancipation in most states. Technically, because you're an adult at 18, you're responsible for having health insurance then, but you're not required to have a policy of your own until you're 26.

Health Insurance for Young Adults

Even if you're married, out of college, living on your own and have insurance available through your job, you can still be covered under your parents' health care plan until your 26th birthday. The age limit is higher in some states: Ohio, for instance, extends your eligibility for your family's plan to age 28. Historically, though, the second and subsequent children on a family plan get coverage for little or nothing, so the burden is apt to be small. If your parents don't have a family plan, or if they're deceased, you'll need your own policy at age 18.

Your Children? That's Another Story

If you have children, however, they won't be covered under your parents' family policy. As of this writing, the Affordable Care Act requires maternity coverage in all small group and individual policies. If your parents' policy is a large group policy, you might not be covered for maternity care. You'll have to arrange insurance for your child. You can get your own family insurance, but an individual insurance policy for your child will probably be cheaper. Insurers can't deny coverage for a pre-existing conditions -- that includes pregnancy -- nor can insurers impose annual or lifelong limits on how much they will pay for an enrollee's health costs.

Adults Are Responsible for Insurance

You're also responsible for your own health insurance if you're legally emancipated -- declared an adult -- which can happen as early as age 14, depending on where you live. To be emancipated, you must have an income sufficient for your living expenses, and your expenses will include health insurance. Starting in 2014, you'll be eligible for Medicaid if you make $15,000 a year or less -- whether you can be emancipated with a $15,000-a-year income is another question -- and like any other adult, you'll be eligible for federal subsidies for health insurance if you qualify for them.

You're an Adult at 18

As a legal adult -- age 18 and older, or emancipated -- you're responsible for making sure you have health insurance. If you're lucky enough to have parents with a family policy, this isn't a problem; you don't have to get your own policy until your 26th birthday. It's more complicated if you're pregnant. Even if you're still on your family's health plan, you may have to buy your own policy to get maternity coverage, and you'll have to arrange insurance for your baby.