What should you sign before your child turns 18, and what happens if you don't?

In the United States, an 18th birthday moves a set of legal rights from the parents to the young adult. The forms that deal with that change can be prepared in the months before the day. Some of the rules are federal: HIPAA, FERPA, Selective Service and the Affordable Care Act apply in every state. Each state sets its own rules for powers of attorney, health care proxies and voter registration deadlines, so the forms one family signs can differ from those used across a state line.

The law firm McLane Middleton sets out plainly what changes on the birthday itself. Once a child reaches 18, the parents' decision-making authority ends. Health care providers also generally cannot share the young adult's health information with the parents unless the young adult gives permission. A short set of signed forms gives some of that access back: a HIPAA release and a health care proxy for medical matters, a durable power of attorney for money, and a consent form for college records. Alongside these come an insurance check and two registrations linked to turning 18. The steps below follow the calendar: the six months before the birthday, the birthday itself, and the first year of adulthood.

Six months before: Get the HIPAA release and health care proxy ready

The medical side needs two documents because each does a different job. In McLane Middleton's guidance on health care proxies for children turning 18, the proxy names an agent and gives that agent access to the patient's medical records. The proxy may only take effect once a doctor activates it. A separate HIPAA release can work immediately.

Most states have their own forms for health care proxies or medical powers of attorney, according to ElderLawAnswers, so the place to start is the form for the young adult's home state. The HIPAA authorization is a separate document that works alongside the medical power of attorney, which means the family needs both. The young adult fills in each one as the principal and names the parent as agent.

Six months before: Find the durable financial power of attorney form

Money needs its own document. Without a durable financial power of attorney, parents have no legal authority to act on an adult child's financial accounts, even in an emergency, ElderLawAnswers warns.

Each state sets its own power of attorney rules, and the requirements for signing and witnessing vary too. Use the home state's form, and complete and witness it the way that state requires.

Six months before: Check who controls the college records

FERPA, the federal student privacy law, gives parents rights over a child's education records only until a fixed point. The US Department of Education says those rights transfer from the parents to the student when the student turns 18 or enrols in a postsecondary institution at any age. A student who enrols before 18 therefore holds the rights from the day of enrolment.

The department allows one exception. A school may share records with parents without the student's consent if the student is a dependent for tax purposes under the IRS rules. The guidance says "may", not "must". The other route is the student's own written consent, so ask the college for its FERPA consent or release form and have the student sign it.

Six months before: Confirm the health insurance runs past 18

Health cover is the one area where the birthday changes less. Under the Affordable Care Act, young adults can stay on a parent's health insurance until age 26, and healthinsurance.org says this holds regardless of where they live or whether they are students.

Not every plan follows that rule, so ask the employer's benefits office or the insurer what kind of plan covers the family. Plans that do not fall under the ACA are one exception on healthinsurance.org's list, and Medicare is another. State rules also do not apply to self-insured plans. Military families have their own limit: TRICARE cover does not extend to age 26 unless the family buys TRICARE Young Adult.

On the birthday: Register with Selective Service

For sons, registration is a legal duty backed by a criminal penalty. Failing to register when required is a felony punishable by a fine of up to $250,000, up to five years in prison, or both. Selective Service also lists the loss of state student aid and of some jobs among the consequences.

Almost all male US citizens and male immigrants aged 18 through 25 must register with Selective Service. The duty also covers US dual citizens and US citizens living abroad.

Before the first election: Register to vote

The US Election Assistance Commission states the age rule plainly: a voter must be at least 18 by Election Day. Registration is a separate step, and the state deadline decides whether a young adult is on the roll in time for an election.

Deadlines differ by state. Some states allow registration on Election Day itself, while others close it up to 30 days before the election. Some states also let people under 18 pre-register, so in those states the form can be filled in before the birthday. The local deadline is published by the state election office.

In the first year: Set up a bank account and credit

The durable power of attorney applies to any bank account in the young adult's name. ElderLawAnswers is clear that a parent without one has no legal authority over those accounts, even in an emergency.

Official guidance on banking and credit for new adults was not available at the time of writing. That includes the credit card rules for young applicants, credit freezes for young adults and how banks handle a parent's power of attorney. The same applies to three other points in this timeline: whether a college student health plan can be waived in favour of a parent's plan, the exact window for registering with Selective Service after the birthday, and how the signed documents should be stored.

Store the signed documents

The signed forms do not all carry the same weight across state lines. Because HIPAA is federal law, ElderLawAnswers says a HIPAA form signed in one state should be recognized in all other states.

The power of attorney and the health care proxy are state documents, and a power of attorney that is valid in one state might not be recognized in another. On every form in the set, the young adult is the principal and the parent is the agent.