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Establishing Paternity in Court

Produced by Massachusetts Law Reform Institute
Reviewed July 2023

When do you need to go to court?

Go to court to decide paternity if:

  • you need to know who the legal father of a child is; or
  • you need to make sure the child has a legal father;
  • and the parents have not signed a Voluntary Acknowledgment of Parentage form.

If you are not married to each other and you have not signed a voluntary acknowledgment of parentage, then you file a Complaint to Establish Paternity.

Read about how to file a Complaint to Establish Paternity.

Who can file a Complaint to Establish Paternity?

  • the mother;
  • a person who says he is the father;
  • the child, even if he or she is under 18 years old;
  • the child's guardian, next of kin or caretaker;
  • the mother’s parent;
  • the mother’s parent or someone the mother asked to represent her, if she died or abandoned her child;
  • the father’s parent or someone the father asked to represent him, if he died his child;
  • 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 welfare or MassHealth.

Who cannot file a Complaint to Establish Paternity?

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 with 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, her husband must be served with a complaint and summons.

He does not have to go to court if he signs a form called an Affidavit of Nonpaternity. This is true even if the mother is divorced from her husband when the paternity case starts.

If there was already a court case that decided the husband is not the child’s father, then he does not have to sign the affidavit or go to court again.

Who are the “parties” in a paternity case?

The person or agency that files a complaint is the “plaintiff.” 

The person you take to court is the “defendant.” 

Both the plaintiff and defendant are “parties” in the case.

If the mother was married to someone else when the child was born or conceived, her husband is also a “party” in the paternity case.

How do courts decide who the father is?

A judge can use tests called “genetic marker tests” to decide who the 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 father of the child.


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

A judge can also decide who the father is without paternity tests.

What are Genetic Marker 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 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 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, he or she can order mother, child, and  “father” to take the tests.

If the mother was married to someone when the child was conceived, she must serve the paternity complaint and summons on her husband or ex-husband.

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 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 he or she makes 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 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.

For more information about genetic marker tests in paternity cases, see Massachusetts General Laws, Chapter 209C, section 17.

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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