Common questions about paternity and paternity tests

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Massachusetts Law Reform Institute

"Paternity" means that there is a legal relationship between a child and their parent.

If the mother is married when her child is born:

  • Her spouse is the child's legal parent as well. 
  • Her spouse’s name will go on the birth certificate. 
  • You can change paternity, if your spouse is not the biological parent.

If a mother is not married when her child is born:

  • The mother is the child’s only legal parent until one of the following actions is taken: 
  • If the mother and father agree about who the father is, you can fill out a form to “establish paternity voluntarily.” 
  • If the parents disagree about who the father is, you need to go to court.
We agree about who the father is. How do we establish paternity?

If you and the other parent are not married and you agree about who the father is, you can fill out a Voluntary Acknowledgement of Parentage form. This is called establishing paternity voluntarily. For unmarried parents, it is not enough to just list a father on a birth certificate. There has to be a signed and notarized Voluntary Acknowledgement of Parentage.

Even if a Voluntary Acknowledge of Parentage is signed, the mother has sole physical and legal custody until a court makes any different decision.

Are you ready to fill out a Voluntary Acknowledgement of Parentage? Learn How to establish paternity voluntarily.

We don't agree about who the father is. How to we establish paternity?

If you disagree about who the father is, file a Complaint to Establish Paternity in court. The judge will decide who the father is. The judge can also make decisions about child support, custody, parenting time and visitation, and protection from abuse.

What about establishing legal parentage in same-sex relationships when the parents are not married?

See LGBTQ Paths to Parentage Security for information about establishing parentage in same-sex relationships.

Who can file a Complaint to Establish Paternity?

The following can file a Complaint to Establish Paternity:

  • the mother;
  • a person who says he is the father;
  • the child, even if they are under 18 years old;
  • the child's guardian, next of kin or caretaker;
  • the mother’s parent, or the mother’s court appointed personal representative, if the mother has died or abandoned the child;
  • the father’s parent, or the father’s personal representative, if the father has died; 
  • an agency that has custody of the child, like the Department of Children and Families; or
  • the Department of Revenue Child Support Enforcement Division if the child ever got public assistance like cash benefits or MassHealth.

Sometimes, a man who says he is the father is not allowed to file a Complaint to Establish Paternity.  He cannot file a Complaint to Establish Paternity if:

  • The mother was or is married to another person, and
  • The child is born during the marriage or within 300 days of the end of the marriage. The marriage can end by death, annulment, or divorce.
What if the mother was married to someone else when her child was born or conceived?

If the mother was married to someone else when the child was born or conceived, or within 300 days after the marriage ended, Massachusetts law treats the spouse as the child's biological and legal parent.

If the married couple agree that the spouse is not the child's biological parent, they can sign a form called an Affidavit of Nonpaternity. You will still need to establish paternity, either voluntarily or in court.

If the mother says that her spouse is not the child's parent, and her spouse disagrees, she will need to bring a case in court to establish paternity. Both the person she says is the parent, and her spouse, will be parties in the case. They both must be served with a complaint and summons.

How do courts decide who the father is?

A judge can use tests called “genetic marker tests” to decide who the biological father is. A judge can order the biological mother, the man who may be the father, and the child to have paternity tests.  After reviewing the test results and any other relevant information, the judge will decide if the man is the biological father of the child. 


A judge may order paternity testing even if the mother is not available.

What are genetic marker (paternity) tests?

“Genetic marker tests” are also called paternity tests. They are simple medical tests that show if a man is the biological father of a child. There are 2 kinds of tests:

  • a cotton swab is rubbed on the cheeks inside the mouth - a “buccal swab,” and
  • a blood test.

The mother, the child, and the man who may be the father are all tested. A lab compares the test samples to see if they match.

The tests are very accurate. They show if a man is the biological father of a child.

When does the court use genetic marker (paternity) tests?

The judge only uses genetic marker tests if someone asks for them and shows the judge why the tests should be used.

How do I ask the court to order genetic marker (paternity) tests?

To ask for paternity tests, file a Motion for Genetic Marker Testing and an affidavit that lists the reasons why you need the tests.


A mother asks the judge for genetic marker tests. Her reason for asking for the tests might be that she had sex with the “father” during the time her child was probably conceived. She writes this reason on the affidavit. See sample. This reason is usually enough for the judge to order tests.

After the judge hears the motion, they can order mother, child, and  “father” to take the tests.

If you refuse to take genetic marker tests, your refusal can influence the judge’s decisions.

At court, the judge looks at the genetic marker test report.

What if I think the genetic marker (paternity) test result is wrong?

The  judge can only look at the report if there is enough evidence to show that the mother and “father” had sexual intercourse during the time when the child was probably conceived.

If you do not want the judge to use the test results when they make the decision, you have to file a written objection.

  • If you get notice of a hearing that is less than 30 days away, you must file your objection when you get the notice.
  • If the hearing is more than 30 days away, you have 30 days from the date on the hearing notice to file your objection.

Even if you file an objection, the judge can still use the paternity tests to decide paternity, if the tests were done correctly.

Who pays for the genetic marker (paternity) tests?

The person who asks for the genetic marker tests pays for them. But the court can decide that the parents must split the costs.

If the court decides that the “father” in the case is the biological father, then he must pay for the tests.

If you cannot afford to pay for the tests, you can file an Affidavit of Indigency and ask the state to pay.  Write the cost of the tests in Section 2 of the Affidavit. If the court accepts your affidavit, the state will pay for the tests.

In a paternity case, what else can the court do besides deciding who the father is?

The court can:

  • order child support,
  • order one of the parents to provide health insurance for your child,
  • make a restraining order to protect you or your child,
  • make a custody order, and
  • make an order about parenting time.

You can ask the court to do these things by checking boxes on the Complaint to Establish Paternity form.


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