It depends on the state, but in Wisconsin the answer can be yes. In Peterson v. Becher (In re Estate of Joseph Gaigg), decided September 22, 2026, the Wisconsin Court of Appeals let a 53-year-old woman prove through a DNA test that a man who died without a will was her biological father, even though her mother was married to someone else when she was born. She was declared his sole heir. Other states have their own rules and deadlines, and this page does not cover them.
What happened in Peterson v. Becher?
Joseph Gaigg died without a will on November 27, 2022. He had no surviving spouse, no children, and no living parents. His niece, Sharon Peterson, applied to administer his estate informally and listed herself, his siblings, and several other nieces and nephews as the interested people.
Dorothy Becher, then 53, objected. She said she was Joseph's only surviving issue (descendant) and that she had not been listed or given notice. She demanded formal court proceedings to decide who Joseph's heirs were, and she asked the court to declare that Joseph was her biological father. Her mother, Virginia, had been married to a man named Gordon when Dorothy was born. Dorothy said Virginia had an affair with Joseph.
Dorothy submitted messages in which Peterson and Joseph's sister Cecelia each acknowledged the relationship. She also submitted the result of a DNA test done after Joseph's death on a hair sample taken from him. The report said Joseph "cannot be excluded as the biological father" because "they share genetic markers," and that "the probability of paternity is 99.99%." The circuit court in Outagamie County ruled for Dorothy, named her Joseph's sole heir, and appointed her personal representative of the estate. Peterson appealed, and the Court of Appeals, District III, affirmed. You can read the court's own opinion on the Wisconsin court system website.
Why does a mother's husband matter, and how can DNA overcome the presumption?
Wisconsin law starts from a presumption that the man married to a child's mother is the child's father. Under Wis. Stat. § 891.41(1)(a), a man is presumed to be the natural father if he and the mother are or have been married to each other and the child is conceived or born after the marriage and before a decree of legal separation, annulment, or divorce. Section 891.39(1)(a) adds that anyone who claims the husband was not the father has "the burden of proving that assertion by a clear and satisfactory preponderance of the evidence."
That presumption is why Dorothy could not simply say Joseph was her father. The court explained that a child of unmarried parents who wants to inherit must first overcome the presumption that the mother's husband is the father. Gordon was married to Virginia when Dorothy was conceived and born, so Dorothy carried the burden of showing he was not her father.
Wisconsin's statutes name genetic testing as one way to do it. Both sections say that genetic test results showing a man other than the husband "is not excluded as the father of the child" and that the statistical probability of that man's parentage is 99.0 percent or higher are enough: § 891.39(1)(a) says they meet the burden of proof, and § 891.41(2) says they rebut the presumption. The statutes add that this works even if the husband is unavailable to be tested. Dorothy's 99.99 percent result cleared that threshold, and the court held it was enough to overcome both presumptions.
Peterson relied on an older four-part test from a 1932 case, which looked at things like whether the husband was absent or incompetent. The court pointed out that the older cases came before the Legislature added genetic test results to these statutes in 1997, and that Peterson had not addressed those provisions. Peterson also argued that the testing had not been ordered by a county child support agency, as one other paternity statute describes. The court said that statute was not the only way to establish paternity here, and that the presumptions in question point to a "genetic test" as the statutes define it.
In what ways can a child born to unmarried parents inherit from a father in Wisconsin?
Under Wis. Stat. § 852.05(1), a child born to unmarried parents is treated like a child of married parents for inheritance from the father if any one of three things is true. First, the father has been adjudicated the father in a paternity proceeding under chapter 767, or by a final court order or judgment from another state. Second, the father admitted in open court that he is the father. Third, the father acknowledged in a writing signed by him that he is the father.
Peterson argued that Joseph had never been adjudicated the father and that there was no evidence he ever acknowledged Dorothy. The court did not rest on an acknowledgment. It held that the first route was still open, because a court can adjudicate paternity in a motion inside the probate case itself. Once Joseph was adjudicated Dorothy's father, she counted as his child. With no spouse, Wis. Stat. § 852.01(1)(b) sends the whole estate to the decedent's issue, so Dorothy took the estate as sole heir. For the general rules on who inherits when there is no will, see our guide on dying without a will.
Did the child have to prove paternity while the father was still alive?
Not under current Wisconsin law, according to this decision. Peterson relied on two older cases, one from the Wisconsin Supreme Court in 1978 and one from the Court of Appeals in 1987, that required a paternity case to be maintained during the father's life. The court explained that the statutes have changed since then. The Legislature amended the survival statute, § 895.01, to cover paternity actions, and it amended § 852.05 to add subsection (4), which says § 895.01(1) applies to paternity proceedings under chapter 767.
The court also relied on Wis. Stat. § 767.80(1), which lets a child, and the personal representative of a deceased man alleged to be the father, "bring an action or file a motion" to determine paternity or to rebut the presumption. If the alleged father has died, § 767.80(1m) says the case may be brought in the county in which "proceedings for probate of his estate have been or could be commenced." A separate statute, § 767.865(2), says that in an action for paternity, if genetic material is available without undue hardship from a deceased respondent or a relative of the deceased respondent, genetic tests shall be administered under § 767.84. It also creates a rebuttable presumption that exhuming the deceased respondent's body to get genetic material is an undue hardship. The court concluded that Dorothy "could move for a paternity determination after Joseph's death, given that Dorothy's right to inherit from him depends on that paternity determination."
Is there a deadline, and why did it not stop Dorothy?
Wisconsin does have one. Section 893.88 says an action for establishing paternity must be commenced "within 19 years of the date of the birth of the child or be barred." Dorothy was 53, so a lawsuit of that kind would have been far too late. Peterson argued the deadline barred her claim.
The court said no, because Dorothy did not file an action. She filed a motion inside Joseph's probate case. Relying on a 2003 decision called DiBenedetto v. Jaskolski, the court explained that the 19-year statute bars only "actions" to establish paternity, not "motions" to establish paternity in a probate proceeding. It stressed that this route is narrow. Such a motion is allowed "for the narrow purpose of determining paternity in a probate proceeding," and the court said it did not read "motion" so broadly as to allow one "in any proceeding." The motion also has to be relevant to the case, and here it was because it helped decide who Joseph's heirs were.
That is a limited holding. Nothing in the opinion says a person can avoid the 19-year limit in general. It says a person whose right to inherit depends on who the father was can raise paternity inside the probate case.
What about the argument that Dorothy would inherit from two fathers?
Peterson argued that letting Dorothy inherit from Joseph gave her a "windfall" because she might also have inherited from Gordon, her presumed father. The court called that argument irrelevant on these facts. Gordon died in 1996 and left his entire estate to Virginia, so Dorothy was not in line to receive anything from him.
The court added that one person can be an heir to several estates when relatives die without wills and that person is a surviving heir under the statute. Peterson did not explain how Dorothy's situation differed. The court also said that letting Dorothy overcome the presumptions supports "the accurate and orderly settlement of estates" by making sure the estate goes to its lawful heirs.
What are the limits of this decision?
Several limits matter before anyone treats this as a rule for their own situation.
It is a Wisconsin decision applying the 2023-24 Wisconsin statutes. It does not bind any other state, and other states have their own rules and deadlines.
The Court of Appeals marked the opinion as recommended for publication in the official reports, and the notice on it says a party may ask the Wisconsin Supreme Court to review it. This page does not predict whether that will happen.
The result depended on the facts of this case. Joseph left no surviving spouse, children, or parents, so his issue took the whole estate, and the 99.99 percent DNA result cleared the statutes' 99.0 percent threshold. Dorothy also submitted family messages acknowledging the relationship, though the court's reasoning rested on the genetic test.
The court did not say consumer DNA results are accepted as court evidence. The test in this case was a genetic test on a hair sample from the dead man, and the statutes and the court control how testing is done.
The case involved a man who died without a will. Intestacy rules generally apply only to property that a will does not give away.
If a will exists and leaves everything to someone else, a biological child's options are different. Our page on being disinherited covers that situation in general terms.
What can relatives who expected to inherit do?
Family members in Peterson's position are not powerless, but the case shows that a late claim can succeed. Peterson's application listed the people she treated as interested persons, and Dorothy's objection began partly because she was left off and given no notice. If someone comes forward claiming to be a child of the dead person, relatives can ask the court for formal proceedings, ask what testing is available, and contest the evidence in court.
In this case, Dorothy also filed messages in which Peterson and Cecelia acknowledged the relationship, so relatives should expect their own words to be offered as evidence. Under § 767.865(1), the personal representative may appear for a deceased respondent in a paternity case whenever an appearance is required. If there is no personal representative, the court may appoint a guardian ad litem, when it finds that appropriate, to represent the deceased respondent's interests.
What steps can someone take if they think a deceased biological father is their parent?
Act quickly once you learn of the death. Wisconsin's 19-year limit for paternity actions shows that time rules exist, and other states have their own deadlines.
Find out where probate has been opened, or where it could be. Under Wisconsin's § 767.80(1m), when the alleged father has died, the case may be brought in the county where probate of his estate has been or could be started (the statute also allows the county where the child resides or is found). The probate court in that county can tell you whether an estate case has been opened.
Ask how genetic testing can be done lawfully. In Peterson the test used a hair sample from the dead man. Do not take or collect anything from a person, a home, or a grave on your own. Ask the court or a lawyer how testing works in your state. Consumer DNA services are often how people first discover a relationship, but this page does not say their results would be accepted in court.
Keep messages, letters, cards, photographs, and documents in which the man or his family acknowledged you. Dorothy's case included such messages.
File an objection or a motion in the probate case, and ask for formal proceedings so a judge decides who the heirs are.
Talk to a probate lawyer, a legal aid office, or a court self-help center about your state's rules.
The opinion is on the Wisconsin court system website: Peterson v. Becher, Appeal No. 2024AP1435. The statutes are posted by the Wisconsin Legislature: § 852.05 on children of unmarried parents, § 891.39 and § 891.41 on the marital presumptions, § 767.80 on who may bring a paternity action or motion, § 767.865 on cases where the alleged father has died, and § 893.88 on the 19-year limit. The court applied the 2023-24 statutes, and the current text on those pages may be updated later.
This is general information about one court decision, not legal advice, and your situation may turn on facts and laws that differ from those described here.
Frequently asked questions
Can I inherit from my biological father if he was not on my birth certificate?
It depends on the state. In Wisconsin, a 2026 Court of Appeals decision let a woman prove paternity of a deceased man through DNA in his probate case and inherit as his sole heir. That ruling applies to Wisconsin only, and other states have their own rules and deadlines for proving a parent-child relationship after death.
Does a DNA test overcome the presumption that my mother's husband is my father?
In Wisconsin, yes in the right circumstances. The statutes say genetic test results showing another man is not excluded as the father, with a statistical probability of parentage of 99.0 percent or higher, meet the burden of proof. The husband need not be available for testing. Other states may handle this differently.
Does the 19-year paternity deadline always block a late claim?
In Wisconsin, it did not block the claim in Peterson, but only because of a narrow probate exception. The court held that the 19-year limit bars paternity actions, not a motion to determine paternity inside a probate case where inheritance depends on the answer. The court stressed that such a motion is allowed only for that narrow purpose and not in any proceeding, and that it does not let a party avoid the deadline.
Can a child still prove paternity after the father has died?
Under Wisconsin law as applied in Peterson v. Becher, yes, at least where the child's right to inherit depends on it. The court held the child did not have to bring a paternity case while the father was alive, because current statutes let a child file a motion in the probate case and allow the case where probate is or could be opened. Rules in other states differ, so check your own.
Are consumer DNA test results enough to prove a father in court?
This page cannot say that they are. People often learn of a biological relationship through a consumer DNA service, but in Peterson the proof was a genetic test of a hair sample from the dead man, and Wisconsin statutes and the court govern testing. A probate lawyer or legal aid office can explain what your court accepts.
This article is general legal information, not legal advice, and may not reflect the most current law or the law in your jurisdiction. Laws vary by state and change over time. For advice about your specific situation, consult a licensed attorney.
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