Mail-in DNA test kits started out as a way to explore ancestry, but they are increasingly showing up in courtrooms. A single saliva sample can uncover an affair from decades ago, a half sibling no one mentioned, or a child conceived outside marriage who now has proof of a biological link. When a parent or grandparent has already died, these discoveries may collide with inheritance rights, trusts, and long-settled assumptions about who counts as family.
A recent Wall Street Journal article highlighted several of these disputes, including a Boston woman who connected with her late father’s family through 23andMe, then later sued for a share of a multimillion-dollar malpractice recovery tied to his death. The case settled in favor of the existing heirs in part because her claim was brought too late, not because she lacked a biological connection. Another case in Utah involved a man who learned through DNA testing that he was the son of a business owner who died without a will. The Utah Supreme Court ultimately ruled that he was entitled to one third of the estate, even though another father had raised him.
These disputes are no longer rare curiosities. As more people in California and across the country upload their genetic information to ancestry sites, the number of potential “surprise heirs” grows. For high value estates and trusts, that means more litigation risk, more emotional upheaval, and more need for careful planning and decisive advocacy when a claim appears.
How California Treats Biological Children and Heirs
Every state has its own rules about who qualifies as an heir. The Wall Street Journal piece shows that some courts focus primarily on genetics, while others weigh factors such as acknowledgement and financial support during life.
In California, several overlapping regimes matter. If a person dies without a will or trust, the intestacy statutes may decide who inherits. Under those rules, children generally include biological children and adopted children. A child born outside marriage can usually inherit from a biological parent if paternity is legally established. DNA evidence can be powerful proof, especially when the alleged parent is deceased and a court must rely on genetic matches, documents, and witness testimony.
Even when there is a will or trust, the language used makes a big difference. Generic terms such as “my children,” “my descendants,” or “issue” can be broad enough to include children whom the family never knew about at the time of signing. The Wall Street Journal article points out that these phrases have already opened the door to claims by DNA discovered heirs in other states. The same risk exists in California, particularly in older documents that did not anticipate consumer genetic testing.
Timing, Statutes of Limitation, and Laches
The law does not allow inheritance disputes to stay open indefinitely. In the Massachusetts malpractice case discussed in the article, the putative heir’s delay in bringing her claim was a key factor in resolving the matter for the existing heirs. Deadlines in California can be just as important as biology.
In probate and trust litigation, strict timelines apply to contests of wills, trust validity, creditor claims, and certain heirship petitions. If a surprise heir waits too long to come forward after notice of a proceeding, a court may bar the claim under statutes of limitation or under the equitable doctrine of laches, which penalizes unreasonable delay that prejudices others. For trustees and beneficiaries facing a late arriving claimant armed with a DNA printout, timing defenses can be as central as any scientific argument.
At the same time, the law also protects people who were genuinely in the dark. When no formal probate was ever opened, or when an heir was actively misled about their parentage, courts may be more receptive to a late claim, especially if assets are still under court supervision or held in trust.
DNA Evidence As Both Sword and Shield
Consumer genetic tests complicate litigation because they are powerful, but not always conclusive. A half match may show that someone is related to the family, but not exactly how. Full sibling or parent child matches carry more weight, yet courts still look for corroborating evidence. In the Utah case mentioned in the article, the court did not rely on DNA alone. It also considered decades of birthday cards with cash that the deceased sent to the child, which supported a finding that he treated the claimant as his son.
For putative heirs, DNA results can be a sword. They can support petitions to establish heirship, reopen an estate, or challenge distributions. For existing heirs and trustees, the same results can be a shield when they show that a person seeking money is not actually related in the way they claim. Either way, litigation quickly becomes expert driven. Courts may hear from geneticists, forensic accountants tracing past support, and psychologists explaining the impact of late life disclosures.
How These Disputes Can Play Out In California Trusts
Consider a California trust established by a successful business owner with children from a long marriage. The trust leaves the bulk of the estate “to my descendants, per stirpes.” Years after the settlor’s death, one of the grandchildren uploads a DNA sample and discovers a match that points to a previously unknown half sibling of the settlor’s oldest child. The new relative eventually concludes that the settlor was her biological father based on a strong genetic match and a brief relationship with him years earlier.
If that person files a petition in California probate court claiming status as a child and beneficiary, several questions arise. Does the trust’s “descendants” language include her, even though the rest of the family never knew of her existence during the settlor’s life? Does California law allow her to establish paternity posthumously, and if so, what standard applies? Are there any time bars, such as expired deadlines to contest a trust after notice of administration?
Now add community property issues if the settlor was married when the child was conceived. A surviving spouse may argue that the trust already allocated community and separate property in a way that did not contemplate another branch of the family tree, while the new heir argues that her share must come from the settlor’s side. That sets up multifront litigation over parentage, trust interpretation, and property characterization.
Planning Responses for High-Net-Worth Families
On the planning side, lawyers quoted in the WSJ article stress that people should revise their documents to address DNA-driven surprises before they occur. For California clients with significant wealth, that means more explicit definitions and targeted clauses. Future focused estate plans may:
- define “child,” “issue,” and “descendants” to include or exclude unknown biological offspring located through genetic testing, depending on the client’s wishes
- set clear cut off dates for presenting heirship claims after death, within the limits of California law
Careful drafting cannot prevent every lawsuit, but it narrows the room for interpretation and gives trustees clearer guidance when new claimants appear.
Litigation Strategy When a DNA Heir Appears
If you are an existing beneficiary or a trustee and a previously unknown relative comes forward, you need a structured response. The first step is to gather the core documents: the will or trust, any amendments, prior accountings, and all notices that have been sent in the administration. The next step is to evaluate the procedural posture. Is there an open probate. Is the trust already fully distributed. Were there prior court orders approving distributions or accountings that could block later claims.
Only then does the biological evidence move to center stage. Counsel will examine the type of DNA test, the level of match, whether additional testing is possible, and whether other evidence, such as correspondence, support payments, or photographs, confirms or contradicts the claimed relationship. In some cases, an early negotiated resolution makes sense, particularly where the legal risk is real and the emotional and reputational costs of a public fight are high. In others, aggressive opposition is appropriate, especially where the claim is weak or clearly out of time.
For newly discovered heirs, timing and tone matter as well. A demand letter that combines proof of biology, references to controlling law, and a willingness to mediate may be more effective than a bare statement that “I took a test and now I want money.”
Why Firms Like Trust Law Partners Are Seeing More of These Cases
As consumer DNA testing becomes routine, late discovered family connections will continue to show up in California trust and estate litigation. The underlying conduct infidelity, secret children, informal support has existed for generations. What has changed is the ease with which patterns can be mapped through databases and shared match lists.
For beneficiaries defending a trust, the challenge is to separate legitimate claims from opportunistic ones and to use timing rules, carefully drafted documents, and evidentiary standards to protect the estate. For putative heirs with strong proof and a genuine connection to the decedent, the challenge is to work through complex procedural rules while facing relatives who may feel threatened and betrayed.
Trust Law Partners focuses on high stakes trust and estate disputes on behalf of beneficiaries and heirs. If your family is dealing with a DNA driven inheritance claim, whether you are defending an estate plan or asserting your rights as a newly identified child or grandchild, we can analyze the facts, explain your options, and build a litigation strategy calibrated to your goals.
Call Trust Law Partners today for a free consultation at 833-982-2079.