At-home genetic testing has transformed how families uncover their histories, but it has also introduced new complexity into estate planning. According to The Wall Street Journal article, “They Found Relatives on 23andMe and Asked for a Cut of the Inheritance,” unexpected discoveries are now leading to inheritance claims from previously unknown relatives, intensifying disputes that have existed for generations.
This is the ultimate modern cautionary tale: The person you thought was your sole child might have an unknown half-sibling who now has a legal claim to your estate.
The issue isn’t simply using general terms like “to my descendants” or “to my children.” The real vulnerability lies in using these terms without precisely defining who is included and, crucially, who is excluded.
Fortunately, a well-drafted estate plan is the definitive defense against unknown heirs and unintended consequences.
The Three Pillars of Protection Against Unknown Heirs
To shield your intended beneficiaries from costly challenges, your estate plan must be exceptionally clear. These three essential steps help ensure your legacy goes exactly where you intend:
- Establish a Formal Estate Plan: The foundation of protection is a legally sound Will and/or Trust. Dying intestate (without a plan) subjects your estate to state intestacy laws, which rely on biological relationships—a perfect scenario for an unknown heir to stake a claim based on genetic proof.
- Define a Closed Set of “Children”: Clarity begins at the first generation. Your documents should specifically list your intended children (by name) and explicitly state that any child not listed is disavowed as an heir. This closes the door to newly discovered half-siblings or biological children unknown to you.
- Coordinate the Definition of “Descendants”: For inheritance purposes beyond your children’s generation (grandchildren, great-grandchildren), the plan should incorporate a similarly limited definition of “descendant” that seamlessly coordinates with the specific list of children defined in Step 2. You may also want to consider limiting further descendants to exclude potential unknown descendants of your children and further generations as well.
The Power of Per Stirpes
While you must specifically name your primary children, it is impractical (and unnecessary) to list every future grandchild and remote descendant. This is where a powerful legal concept comes into play: per stirpes.
Per stirpes (Latin for “by the branch”) is a legal term defined for estate planning that allows a deceased person’s share of an inheritance to pass down to their descendants. It’s a mechanism of representation. For example, if you have two children (A and B), and A dies before you, A’s share would pass per stirpes to A’s children (your grandchildren).
By defining your children narrowly (Step 2) and then using the legal concept of per stirpes (Step 3) for all subsequent generations, you ensure that only the family lines you explicitly approve can benefit. However, as noted above, further consideration should be given to the possibility that your children or further descendants may have unknown descendants of their own. This is where a carefully crafted definition of “descendants” comes into play within your estate planning documents to ensure that further generations can inherit property by representation (per stirpes), but that those generations are again limited to those actually included in your own personal definition of family. This is particularly vital if your estate plan creates further trusts for future generations, such as dynasty trust structures (where children’s shares are held in further trust for their lifetime and then passed down to their own descendants).
As the legal landscape continues to grapple with the complexities introduced by genetic testing, the lesson for anyone writing or updating their estate plan is simple: specificity is paramount. According to legal experts, “If you leave property to ‘all your nieces and nephews’ as a class gift, and someone can prove through DNA to be a niece or nephew, he will be included in the class gift.” (Stouffer Legal, 2021). The best practice is to use precise, intentional language to name or exclude, giving your wishes the legal weight they deserve. Additionally, if the intent is that assets are held in further trust structures for multiple generations, you should consider all possible scenarios for future potential unknown heirs/descendants that you may want to exclude.
Usually, this is accomplished by taking a dual approach to the problem in your legal documents. First, name the individuals whom you consider to be your children. Legally, you will be closing the set of individuals who can make a claim as a member of the next generation. Second, your legal document should clearly define the word “descendant” by covering the situations under which you would or would not consider someone to be a descendant. This definition would apply to the descendants of your children (or any other family member who is named as your beneficiary and whose descendants might inherit your assets). For example, the definition might address adoption, assistive reproductive technology, the child who is conceived before death but born after death, and the child who is born out of wedlock.
A comprehensive estate planning platform like Wealth.com is perfectly positioned to operationalize these three pillars of protection. First, users create estate planning documents that are legally binding, override default laws, and provide guidance in areas where laws are silent. Second, the guided forms require users to explicitly name a closed set of children, if the user has at least one child, and automatically provide a comprehensive definition of “descendant” to cover unusual circumstances and of “per stirpes” to describe who qualifies as a member of the user’s subsequent generations. This integrated approach ensures that the digital convenience of the platform results in a legally robust document, giving users confidence that their estate plan is fortified against the modern challenges posed by DNA discovery and unexpected claims.
Sources and Further Reading
- The Wall Street Journal. “They Found Relatives on 23andMe—and Asked for a Cut of the Inheritance.” WSJ, 2024
- Stouffer Legal. “DNA Tests Are Causing Issues in Estate Planning and Administration.” Stouffer Legal Blog, July 16, 2021
- Morton Law Firm. “Navigating Estate Planning with DNA Test Kits.” Morton Law Firm, October 18, 2024



