Wisconsin Department of Children and Families

Protecting Children, Strengthening Families, Building Communities




Genetic Tests


Genetic tests can be done either by a swab test or a blood test. Most places do the swab test. For the swab test, cotton swabs are rubbed inside the mouth to obtain cell samples. In both types of testing, samples are taken from the man, the mother and the child. The results from these tests will determine the probability of a specific man being the father. If you are not sure if a man is the father, you should ask for genetic testing.

Local child support agencies offer genetic testing at a reduced cost. If the parents were not married at the time of the child's birth, legal fatherhood must be decided before a court will order child support. If a child was born when the mother was married, her husband is the legal father.

A court uses the test results to rule on paternity when the man or the mother are not sure or do not agree on the paternity of the child. If the test shows a 99% or greater probability of fatherhood, the man will be the legal father under Wisconsin law. The man has a right to object to the test results in court.

Who pays for the genetic tests?

  • The child support agency pays for the tests until paternity is established.
  • If the tests show the man is the father, he and/or the mother may be ordered to pay for the tests.
  • If the tests show that the man is not the father, he will not be charged for the tests.

More information about fees for genetic testing