Did my child become a citizen when I did?

This page is about children who became citizens after birth, through a parent. It is general information, not legal advice. For your own naturalization, see What happens at the citizenship interview and oath ceremony.

How does a child become a citizen automatically?

Through a law called the Child Citizenship Act of 2000. It changed section 320 of the Immigration and Nationality Act. Under it, a child born outside the U.S. automatically becomes a citizen on the day all of these are true, on or after February 27, 2001:

1. The child has at least one parent who is a U.S. citizen, by birth or by naturalization. This includes an adoptive parent.
2. The child is under 18.
3. The child is a lawful permanent resident (has a green card).
4. The child is living in the United States in the legal and physical custody of the citizen parent.

The order does not matter. The child might get a green card first and you naturalize later, or the other way around. What matters is that all four were true at the same moment, before the 18th birthday.

There is no application to "become" a citizen this way. It just happens. Papers like a passport or certificate only prove it.

Which conditions trip people up?

"Under 18" means before the 18th birthday. Not the year they turn 18. The day.

"Green card" means approved. A child with a pending green card application is not yet a permanent resident. If you naturalize while your child's case is pending, the child can still become a citizen on the day the green card is approved, if it is before age 18 and the other conditions still hold.

"Your child" has a legal meaning. USCIS policy on who counts as a child sets these rules:

• Biological children usually qualify.
• Adopted children can qualify if the adoption is full and final, ends the legal tie to the earlier parents, and meets the immigration law rules for adopted children. Those rules are technical. Have a lawyer check the adoption papers.
• Stepchildren do not qualify through a stepparent unless the stepparent legally adopted them under those rules. A stepchild can still qualify through their own citizen parent.
• Born to unmarried parents, and the father is the citizen? The father must have legitimated the child. Legitimation generally has to happen before age 16, while the child is in the father's legal custody, under the law of the place where the child or father lived.

"Living in the United States" means living here. A child who stayed abroad with a grandparent did not meet the condition during that time. (There is an exception for some children of U.S. military members and U.S. government employees stationed abroad.)

What does legal and physical custody mean?

Physical custody means the child actually lives with you.

Legal custody means you have responsibility for and authority over the child. USCIS presumes it in these situations, unless there is evidence that says otherwise:

• You are married to the child's other parent and live together. This is true even if the child was born before you married.
• The other parent has died and the child lives with you.
• You never married the other parent and the child lives with you. A citizen father must also have legitimated the child.
• You are divorced or separated and a court gave you primary care, or joint custody. You don't need sole custody.
• The court order says nothing about custody, and the child actually lived with you without dispute.

A private custody agreement between parents usually does not count, unless your state's law recognizes it. A court order made after the child turned 18 that changes custody "back in time" does not count.

How do we prove it?

You have two main options. Many families do both over time.

Option 1: a U.S. passport. A valid passport proves citizenship, and it usually costs much less than an N-600. For children under 16, both parents usually must appear, or the absent parent signs Form DS-3053 before a notary.

The State Department's citizenship evidence page (updated October 5, 2026) asks a child who became a citizen through a parent for:

• The child's foreign birth certificate listing the parents
• Proof of the parent's citizenship: U.S. birth certificate, Consular Report of Birth Abroad or Certificate of Naturalization
• Proof of the child's green card: the card, or a foreign passport with the I-551 entry stamp
• The parents' marriage certificate, if they were married when the child entered the U.S. and before the child turned 18
• Custody papers, if the parents were not married when the child entered, or divorced after the child entered
• Proof the child lived in the U.S. with the citizen parent. A green card alone is not enough. Bring at least two: school or day care records, utility bills, job records, car registration, a lease or deed, medical records or passport stamps.
• Legitimation papers, if the parents were not married at the birth, such as a later marriage certificate or a court order

Option 2: a Certificate of Citizenship (Form N-600). USCIS issues it after you file Form N-600. It never expires, unlike a passport. A citizen parent or legal guardian must file for a child under 18. A person 18 or older files for themselves.

• Fee: $1,385 on paper, $1,335 online. You can ask for a fee waiver with Form I-912, but only on paper.
• Filing: online through a USCIS account, or by mail. From California, paper N-600s go to the USCIS Phoenix Lockbox. Check the N-600 page for the address the day you mail.
• Photos: USCIS sets an appointment at a local Application Support Center. If the child misses it without notice, USCIS may treat the case as abandoned.
• Interview: usually the child and the citizen parent attend. USCIS may skip it if your naturalization certificate and other records already prove everything.
• Oath: children under 14 don't take an oath. USCIS issues the certificate after approval.
• If denied: you may appeal within 30 days (33 if the decision was mailed).

For help with fees, see How much citizenship costs.

What papers prove each condition?

USCIS lists these documents for Form N-600, when they apply. The same papers help with a passport application:

• The child's birth certificate
• Your marriage certificate, and proof any earlier marriage ended (divorce decree or death certificate)
• Your proof of citizenship: Certificate of Naturalization, U.S. birth certificate, U.S. passport or other proof
• The child's green card, or an I-551 stamp in a passport
• Legitimation papers, if the child was born to unmarried parents and the father is the citizen
• Custody papers if you were divorced or separated
• The full adoption decree, if adopted
• Proof the child lived with you before age 18, such as:
  • school records showing the same address as yours
  • medical or vaccination records with your address
  • your tax transcripts listing the child as a dependent
  • a notarized statement from you or the other parent about when the child lived with you
• Proof of any legal name changes

Keep a full copy of everything you send.

What should my child do now?

If your child is already a citizen, a few things change:

• Get proof before the green card expires, so your child always has a valid document.
• Use the passport or certificate as proof of status once you have it.
• Don't file Form N-400 for the child. A citizen does not need to naturalize.
• At 18, they can register to vote. See I'm a citizen now: passport and voting.

If you are not sure your child qualifies, don't let them claim to be a citizen on a job form, a voter form or anywhere else yet. A false claim to citizenship can cause serious immigration problems. Get a lawyer's opinion or file the N-600 first.

What if my child missed it?

If your child turned 18 before all four conditions were true, they did not become a citizen through you. That is disappointing, and it is not the end. Your child can apply for citizenship on their own with Form N-400 once they meet the usual rules, usually after 5 years as a green card holder.

If all four conditions were met before February 27, 2001, older laws apply. Talk to a lawyer; the answer depends on the exact dates.

What mistakes should I avoid?

• Assuming a child who turned 18 before your oath day qualifies.
• Forgetting the child must have been a green card holder at that moment.
• Overlooking legitimation when the father is the citizen and the parents never married.
• Relying on a private custody agreement instead of a court order.
• Paying for an N-600 when a passport would meet your needs right now.
• Letting a child with unclear status claim citizenship before you confirm it.

Who can help?

The first four are Bay Area offices; the last line works anywhere in California. Contact them to confirm hours, languages and openings. Being listed here is not a referral or a promise of service.

• Community Legal Services in East Palo Alto, for low income San Mateo and Santa Clara County residents: 650-326-6440. Walk in help Monday to Friday, 9 a.m. to 1 p.m., 1861 Bay Road.
• Immigration Institute of the Bay Area, Redwood City: consultations by appointment, (650) 587-1558.
• SIREN, San Jose: (408) 453-3003, by appointment.
• Asian Law Alliance, San Jose: (408) 287-9710.
• Anywhere in California: the state's map of free immigration legal services, or (916) 651-8017.

Only an attorney or a DOJ accredited representative may give you legal advice. See Free legal help in the Bay Area.

Questions people ask

I naturalized when my son was 16. He had a green card and lived with me. Is he a citizen? Very likely, yes, as of your oath day. Get him a passport or file Form N-600 to prove it.

My daughter got her green card at 17, after I was already a citizen. Does that count? Yes, if she lived with you in your custody. She became a citizen the day her green card was approved.

My ex has custody, and I'm the citizen. Does my child qualify? Usually not, unless you share joint legal custody and the child lives with you. Talk to a lawyer.

Do I have to file the N-600? No. It is optional proof. Many families use a passport instead. The certificate is helpful because it never expires.

Is there a checklist I can print?

Your citizenship may have opened the door for your child too. Take the time to prove it. It protects them for life.