Entertainment Love and Romance How to Determine Paternity for Child Support How Does Your State Determine Paternity? Share PINTEREST Email Print Jamie Grill/Stone/Getty Images Love and Romance Relationships Sexuality Divorce Teens LGBTQ Friendship By Debrina Washington Family law attorney and writer University of Pittsburgh School of Law Skidmore College Debrina L. Washington is a New York-based family law attorney and writer, who runs her own virtual practice to assist single parents with legal issues. our editorial process Debrina Washington Updated March 05, 2018 Laws that determine paternity can vary by state and may differ depending on whether parents are married to each other or not. Because paternity plays a key role in deciding child support obligations, it’s important to understand the factors courts consider when determining paternity. Here’s an overview of how paternity may be determined. How Courts Determine Paternity for Married Parents Some states presume that a husband must be the father if he was married to the mother at the time of conception/birth. Some states take the presumption of paternity so far that they won't even consider blood test results. Certain states have a written code that only presumes paternity if the spouses were living together at the time of conception. Depending on where you live, a married man may challenge the paternity of a child born to his wife. In such cases, a court will make a determination based on: Blood Tests: Some states require blood tests to be completed within a certain timeframe (i.e., Two years after the child's birth). After that time, a court will not accept a blood test, presuming that a father recognizes a child as his own and the child has accepted the father as his parent.Whether or not the father holds himself out to the be the father of the childWhether another man claims paternity of a child If married parents separate, it is assumed that both parents will be required to support the child. During a custody hearing, unless a father contests paternity, both he and the child's mother will be responsible for child support. Paternity Determination for Unmarried Parents States vary on how they determine paternity when the mother and father were not married. In such cases, courts may consider: Blood Tests: Whenever paternity is contested, a court, on its own motion or at the request of one of the parents, can order genetic testing to determine paternity.Declaration of Paternity: This may be signed by the father before the mother and child leave the hospital; it is generally signed within one or two days of the child's birth.Name on the Birth Certificate: A father's name may be on the birth certificate if:(1) he completes a voluntary declaration of paternity or(2) if he goes to court and accepts paternity.A "father" holds himself out to be the child's parent: A court will consider the fact that a "father" has established a relationship with a child for a period of time. The longer the established relationship between parent and child, the better chance the man has that the court will consider him an to be the father. Prior to hearings regarding custody or child support, be sure to gather the documents and information you have that show proof of paternity. If you do not have any proof, there are steps that you can take to try to establish paternity.