Can Paternity Be Established Through DNA From Relatives?

When the alleged father is unavailable or has died, DNA from close relatives can sometimes help answer the parentage question, and Washington law gives courts specific tools for certain situations. The details matter, so it is worth understanding what the statute actually allows. The Law Office of Chad Foster helps Snohomish County clients with parentage matters.

The Short Answer

Paternity questions do not disappear just because the alleged father cannot be tested directly. Sometimes he has died, sometimes he cannot be located, and sometimes he simply refuses to cooperate. In these situations, families often ask whether testing a relative can fill the gap. The general answer is that relative testing can be scientifically useful, and Washington's Uniform Parentage Act, chapter 26.26A RCW, gives courts genetic testing authority within a parentage case, including a specific provision addressing identical siblings. What the court can do depends heavily on the facts and on which part of the statute applies.

How the Science Generally Works

Because close relatives share portions of their genetic material, DNA from a father's parents, siblings, or children can sometimes support conclusions about whether a person was the child's biological parent, even when the man himself is not available to be tested. This is sometimes called kinship or relationship DNA analysis. The reliability of these methods varies with the relationship being tested and the quality of the samples, and these are technical questions for an accredited laboratory rather than a lawyer. The key legal point is that having a plausible scientific method is only half the picture. The other half is whether a court has the authority to order the testing and to rely on the result. For related guidance, see Can I Challenge Paternity After It's Been Established.

The Court's Authority to Order Genetic Testing

In Washington, a court's power to order genetic testing lives inside a parentage proceeding. Under RCW 26.26A.310, the court generally orders the child and the individual whose parentage is being adjudicated to submit to testing when a party supplies the required sworn statement. If the woman who gave birth is unavailable or declines testing, subsection (5) permits testing to proceed with the child and the individual whose parentage is at issue. That section does not expressly give courts blanket authority to compel testing of any relative simply because kinship testing could be scientifically useful. For related guidance, see Can Paternity Be Established After the Child Turns 18.

The Identical Sibling Provision

Washington law includes one especially specific rule about relatives. Under RCW 26.26A.350, if the court finds reason to believe that an alleged genetic parent has an identical sibling, and there is evidence that the sibling may be a genetic parent of the child, the court may order genetic testing of that sibling. This provision exists because identical siblings share the same genetic profile, which can make it impossible for standard testing to distinguish between them. The same section allows the court, when more than one identical sibling is identified as a possible genetic parent, to rely on nongenetic evidence to decide which sibling is actually the parent. This is a narrow but important tool. It should not be read as general statutory authorization to compel parents, ordinary siblings, or children of a deceased alleged parent to provide DNA. Outside the identical-sibling situation, the availability of relative testing may depend on consent, other procedural authority, the evidence offered, and the court's rulings in the particular case.

When the Alleged Father Has Died

The most common reason families turn to relative testing is that the alleged father has passed away. In that situation, a case can still move forward, because the parentage statute allows certain people to bring or continue a proceeding on behalf of someone who is deceased. Under RCW 26.26A.405(7), a representative authorized by law may act for an individual who would otherwise be entitled to maintain a proceeding but is deceased, incapacitated, or a minor. That opens the door to pursuing a parentage determination even after death, though how the court gathers reliable evidence in that setting depends on what samples and relatives are available and on the specific facts of the case.

Because chapter 26.26A RCW does not lay out a single universal rule for every kind of relative and every scenario, cases involving a deceased alleged father are often fact-intensive. What is available, whose cooperation can be obtained, and what the science can support all shape the strategy. This is one reason these matters benefit from careful legal and scientific coordination rather than assumptions about what a home DNA kit can prove.

Why This Comes Up in Snohomish County Families

For families across Snohomish County, relative-based parentage questions frequently surface at emotionally difficult moments, often after a death, when an estate is being settled or a child's benefits are at stake. A child seeking to establish a connection to a father who has died may need to rely on the father's parents or siblings, and understanding what a court can and cannot order helps set realistic expectations. It also underscores the value of acting promptly, because relatives and usable samples become harder to secure as time passes.

Getting Clear Guidance

If you are trying to establish parentage and the person at the center of the question is unavailable or has died, you do not have to figure out the science and the law on your own. Understanding which statutory tools apply to your facts, and how to present the evidence a court will accept, can make the difference between a stalled case and a resolved one.

If you are facing a parentage question that involves a relative's DNA or a father who has passed away, the Law Office of Chad Foster can help you understand your options in Snohomish County and beyond.