Whose Last Name Does the Baby Get If You’re Not Married?

When two unmarried people have a baby, it can raise questions about the baby’s last name. 

Generally, if an unmarried mother gives birth, she can choose the child’s last name. 

In this article, we will explore the options for unmarried parents when naming their child, including the legal considerations.

Legal Aspects of Naming a Baby

In the United States, no federal laws govern the last name of a child born to unmarried parents. Parents are generally free to choose any last name they wish for their child.

As parents, you have several options for naming your baby. These include:

  • The Father’s Last Name – The baby can take the father’s last name. This is the most common option for married couples.

  • The Mother’s Last Name – The baby can take the mother’s last name. This is a good option if the mother has a strong family tradition or the father is not involved in the child’s life.

  • Combination of Both Last Names – The baby can have a combination of the mother’s and father’s last names. For example, if the father’s last name is Smith and the mother’s last name is Jones, the baby’s last name could be Smith-Jones or Jones-Smith.

  • Any Last Name You Want to Choose – Parents are free to give their children any last name they want. Parents are not obligated to pass down a father or mother’s last name to their child. 

Famous Examples of Parents Giving Their Children Different Last Names

Here are many famous examples of parents giving their children different last names:

1. Angelina Jolie and Brad Pitt: Jolie and Pitt’s six children have a hyphenated last name (Jolie-Pitt).

2. Gwyneth Paltrow and Chris Martin: Paltrow and Martin’s children have a hyphenated last name (Martin-Paltrow)

3. Actor Ethan Hawke and his then-wife, actress Uma Thurman, named their daughter Maya Ray Thurman-Hawke.

4. Elon Musk and Claire Boucher (Grimes) named their son X Æ A-Xii. The last name combines both parents’ initials and a nod to their favorite aircraft, the Lockheed A-12.

5. Musician John Lennon and his wife, artist Yoko Ono, named their son Sean Taro Ono Lennon.

Who Decides The Child’s Last Name if the Parents Are Not Married? 

If the parents are unmarried, deciding what last name to give the child can become more complex. 

In most states, an unmarried mother is given the authority to decide on the child’s last name. She can give the child her last name, the father’s last name, a hyphenated last name, or a completely different last name. 

In most cases, if the parents are not married, and the father is not listed on the birth certificate, he has no legal say in naming the child. 

This is because he does not have parental rights or responsibilities without being legally recognized as the child’s father. 

However, if the father is listed on the birth certificate or has established paternity through a court order, he will have the right to participate in the naming process and have a say in the child’s name. 

How Does an Unmarried Father Get a Say in His Child’s Name? 

If an unmarried father wants to have a say in his child’s name, he must establish legal paternity. There are several ways that this can be done, including:

  • Signing a voluntary acknowledgment of paternity at the hospital when the child is born.

  • Filing a petition to establish paternity with the court and obtaining a court order establishing paternity.

Once paternity has been established, the father will have legal rights and responsibilities for the child, including the right to participate in decisions regarding the child’s name. 

What To Do If a Father and Mother Cannot Agree on Their Child’s Name? 

Sometimes, if the parents cannot agree on a name, a court may be asked to decide on the child’s name. 

To get a court to allow you to name your child, you will generally need to establish legal paternity first. Once paternity has been established, a father can petition the court for a say in the child’s name. 

Here are the steps a father would need to follow:

1. File a Petition

File a petition with the family court requesting that you be given a say in naming your child. The petition will outline your reasons for wanting to be involved in the naming process and may include supporting evidence such as text messages, emails, or other documentation.

2. Attend a Court Hearing

Attend a court hearing where the judge will listen to both sides of the case and decide whether you will be allowed to participate in naming the child.

3. Provide Evidence

You may need to provide evidence to support your case, such as your relationship with the child or your involvement in the child’s life.

4. Go To Mediation

Before going to court, I recommend mediation. A couple can use mediation as a way to agree on their child’s name. 

Mediation is a form of alternative dispute resolution that involves a neutral third party, the mediator, who helps the parties negotiate a mutually acceptable solution. 

In this case, the mediator would assist the parents in coming up with a name they both agree on.

Mediation can be a helpful tool for resolving disputes related to children because it allows the parties to work together to find a solution that is in the child’s best interests. It can also be less adversarial and less expensive than going to court.

During mediation, the mediator will work with the parents to identify their concerns, interests, and goals related to their child’s name. They will then help the parents explore different options and develop creative solutions that meet everyone’s needs. 

The mediator will not make decisions for the parents but will facilitate the negotiation process and help the parties reach an agreement.

5. Await the Court’s Decision

Once the court has heard both sides of the case, they will decide whether you will be allowed to participate in naming the child. If the court rules in your favor, you can help choose your child’s name.

Personal Preferences For Your Child’s Name

Ultimately, the decision of what last name to give the child is personal and should be based on the preferences of both parents. 

Some parents may decide to hyphenate their last names, creating a new last name for their child, representing both sides of the family. 

Others may give the child the mother’s or father’s last name, depending on their beliefs and values.

It’s worth noting that deciding what last name to give the child may also impact future decisions, such as who will have legal custody or who will be responsible for child support. 

As such, it’s important for parents to carefully consider all options and seek legal advice if necessary.

Can You Change Your Child’s Name if You Change Your Mind Later?

Most states allow parents to change a child’s name on the birth certificate without going to court within a certain timeframe after the child’s birth.

For example, in California, parents have up to one year from the child’s date of birth to request a name change on the birth certificate without going to court. 

In New York, parents have up to 60 days after the child’s birth to request a name change on the birth certificate without a court order. 

It is important to remember that the requirements for changing a child’s name can vary depending on where you live. 

If you are outside the time granted to amend a birth certificate and want to change your baby’s name, you must file a petition with the court and provide a valid reason for the name change. 

Some common reasons for changing a baby’s name include correcting a mistake on the birth certificate, changing the baby’s name to match the parents’ preference or cultural traditions, or changing the baby’s name due to a change in circumstances, such as divorce or adoption.

The specific requirements and procedures for changing a baby’s name after birth will depend on your state. In some places, you may need to appear in court and provide evidence to support your petition for a name change. In contrast, you can complete the process in other states by filing paperwork with the Registrar of Vital Statistics or the Department of Health.


In conclusion, if you’re not married and expecting a baby, you have several options for naming your child. Parents are responsible for the child, and you can choose the baby’s last name together. 

You can give the baby the father’s last name, the mother’s last name, or a combination of both. Remember to register your child’s birth and make the best decision for your family.

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Tim McDuffey is a practicing attorney in the State of Missouri. Tim is a licensed member of the Missouri Bar and Missouri Bar Association.

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