Defining Paternity and Parentage:

Paternity, by definition, means the state of being the father of a particular child. From a legal perspective, paternity refers to the legal relationship between a father and his child.  A biological father is not necessarily a legal father. It is the process of “establishing paternity” that then establishes the legal relationship and associated rights and obligations of the legal father.

Washington state law acknowledges same-sex marriages and domestic partnerships with equality. The statute language speaks of parentage (link) more broadly and gender neutral, rather than assuming a male father.

Establishing Parentage or Paternity:

Parentage in Washington State can be established by presumption, acknowledgement (voluntary), or through a parentage action in court (involuntary).


If parents are married or in a domestic partnership when the child is born, parentage is presumed and automatically established. The person who gives birth is one legal parent and the spouse or domestic partner is presumed as the second legal parent. The presumed parents are listed on the birth certificate and automatically have legal parental rights and obligations.

When a child is born and the parents are not married or in a domestic partnership, the legal father or second parent is not presumed and parentage or paternity must be established in order to determine a legal relationship between the second parent and the child. Until paternity is established, the child does not have a legal father or second parent.


Unmarried parents may jointly agree to identify the biological father as the acknowledged father by signing an “acknowledgement of paternity”, which establishes legal paternity of a child. (RCW 26.26.300). Both parents must sign the acknowledgment and it must be done with a notary and properly filed with the state. This is often done at the hospital when the child is born. This method is considered “voluntary” since there is no dispute over parentage.

Parentage Action:

When a voluntary agreement cannot be reached, Washington state law permits interested parties to file a parentage action in state court to make a legal determination about a child’s parents or paternity. This method is referred to as “involuntary” because someone is disputing paternity, which is why it becomes a court issue.

For example, if an unmarried father is attempting to establish paternity and the mother does not cooperate, court adjudication may become necessary. The father may file a parentage action, seeking the court to establish legal paternity. The court may need to order genetic testing to confirm the unmarried father’s paternity. If the court issues a parentage order, the man seeking to establish paternity becomes the adjudicated legal father.

Benefits of Establishing Parentage or Paternity:

There are many reasons that make it beneficial to establish a child’s legal parentage, legally, practically, and emotionally. Here are some of the reasons why legal establishment of parentage or paternity can be advantageous to all involved:

  • The child is able to have a relationship with both parents
  • The child can have access to family history and medical history, and may be able to establish meaningful connections with extended family members.
  • The child is given certain rights related to property, inheritance rights, and eligibility for benefits.
  • Mothers are able to share the responsibilities of parenting
  • Establishing paternity provides the basis for requesting child support and allows mothers to share the cost of raising their child.
  • With established legal paternity, fathers may assert their parental rights and ask for court-ordered custody, child support, or parenting time.
  • Fathers are able to show their investment in their child’s life and to develop a bond with their child.

Legal Representation:

If you have questions about parentage action or paternal rights in Washington state or if you are seeking legal counsel, please contact an experienced family law attorney as soon as possible. This just begins to shed light on the state’s comprehensive paternity and parentage laws. Our experienced family law attorneys are strong advocates, recognizing the unique aspects of each case. We have the expertise and ability to provide advice and representation to anyone with an interest or concern related to legal parentage, with all degrees of complexity. We are committed to helping you achieve the best outcome in your case, insisting on the best interest of your children.