Consanguinity in American Trust & Estate Law 2026

1. Few concepts in estate law are as foundational and as complex as consanguinity. The principle, rooted in blood relationships, has long determined who inherits, who is excluded, and how trust and estate professionals untangle intestacies to satisfy the courts. While the framework itself is centuries old, modern family structures and evolving state laws mean that consanguinity continues to change, requiring estate and trust professionals to stay alert to its nuances. 

   What is Consanguinity? 

   At its simplest, consanguinity describes the blood relationship between individuals who share a common ancestor. In a legal context, it serves as the backbone for intestate succession—the process by which courts determine heirs when someone dies without a will. 

   Consanguinity comes in two main forms: 

   • Lineal consanguinity: direct ancestor–descendant relationships such as parents, children, and grandchildren. 
   • Collateral consanguinity: relatives who share a common ancestor but are not direct descendants, such as siblings, aunts and uncles, and cousins. 

   Historically, inheritance law prioritized consanguinity above all else, operating under the assumption that keeping assets within the bloodline best honored the decedent’s legacy. Modern estate planning, however, provides ways to affirm—or intentionally bypass—those assumptions. 

   HeirSearch’s Consanguinity Chart 

   When a decedent dies intestate, most jurisdictions begin by looking to the closest relatives under degrees of consanguinity. At HeirSearch, we refer to these degrees as Search Types, which we outline in our Consanguinity Chart. In our Search Types we identify, locate, prove and report the following: 

   • Direct: one specific person. The search can be expanded to locate the person’s issue (lineal descendant) or the executor of the estate, if the person to be located is deceased. 
   • Multiple: multiple people related to a specific matter. The search can be expanded to locate a person’s issue (lineal descendant), or identify the executor of an estate, if any or all of the search subjects to be located are deceased. 
   • Lineal: decedent’s issue (lineal descendant). If no living lineal descendants survive, the search may be expanded to relatives one generation back –Level I Heirs. 
   • Level I Heirs: parents, siblings (whole or half blood), nieces, and nephews. 
   • Level II Heirs: grandparents, aunts, uncles, and first cousins. 
   • Level III Heirs: great-grandparents, great-aunts and uncles, second cousins, and beyond. 

   Each type must be exhausted of living heirs before we consider the next. This process may appear orderly on paper, but in practice, it often results in unexpected complications, especially as family structures evolve. 

   For example, Pennsylvania law treats half-blood relatives the same as full-blood relatives, eliminating distinctions that once divided inheritances between children of first and second marriages. Adopted children are widely recognized as consanguineous descendants of their adoptive parents, even though no biological link exists. At the same time, relatives by marriage remain excluded from inheritance under consanguinity statutes unless expressly included in an estate plan. 

   The Limitations of the Bloodline Approach 

   Although consanguinity offers a clear legal roadmap, it is not always aligned with a decedent’s actual wishes. Sharing DNA does not necessarily mean sharing values, financial acumen, or emotional closeness. Without a will, wealth may pass to relatives who had little or no meaningful connection to the decedent, while friends, caretakers, or step-relations are left out entirely. 

   This disconnect underscores why estate planning remains essential. Well-drafted wills and trusts give individuals the ability to define their own priorities rather than leaving distribution to default statutory rules. They can also prevent disputes, reduce the likelihood of litigation, and safeguard against the risk of distant relatives or the state claiming an estate. 

   Alternatives & Planning Tools 

   For estate professionals, consanguinity is both a guiding principle and a potential obstacle. The following strategies highlight ways in which clients can ensure their estates are distributed according to personal intent rather than statutory hierarchy: 

   • Trusts: Provide structure and oversight, allowing assets to benefit heirs while protecting against mismanagement. Trusts can also incorporate no-contest clauses, deterring challenges by disinherited relatives. 
   • Charitable giving: Enables clients to direct wealth toward causes and institutions that reflect their values, reducing reliance on consanguinity altogether. 
   • Business succession planning: Prevents the automatic transfer of control to family members who may be unqualified or uninterested, instead securing continuity through deliberate planning. 
   • Blended families: Stepchildren are rarely considered heirs under consanguinity. Explicit estate planning ensures these individuals are included where intended. 
   • Pet trusts and nontraditional heirs: Increasingly, individuals wish to provide for pets, companions, or caretakers who played a significant role in their lives. Planning tools now make these options viable. 

    By helping clients understand both the reach and the limits of consanguinity, estate professionals can craft strategies that align with modern realities. 

   Forensic Genealogy & HeirSearch 

   Consanguinity remains a cornerstone of American trust and estate law, but it is not the whole story. As family structures diversify and societal definitions of kinship continue to evolve, lawyers and administrators must balance statutory frameworks with the practical realities of inheritance.  

   Despite the best planning, many estates still require heirship determination through consanguinity. This is especially true in cases of intestacy or when distant relatives must be located and verified. 

   HeirSearch specializes in this work. Our forensic genealogists apply state-specific laws of descent and distribution, document kinship through reliable evidence, and provide courts with the accurate, defensible reports required to fulfill fiduciary duties. Whether identifying a single missing heir or conducting broad multi-level searches, our team brings clarity to one of estate law’s most complex areas. 

   Do you need help establishing kinship to solve an estate matter? 

   Since 1967, HeirSearch has harnessed our forensic genealogy expertise to complete thousands of worldwide searches. We are proud to have achieved a success rate of 97% across our heir searches. 

   If you are a fiduciary professional needing to establish heirship to satisfy the court, HeirSearch can help. We offer no-cost, no-obligation consultations, even if you are not planning to start a search immediately. 

   Thanks for reading this month’s HeirSearch blog, and please reach out with any questions — we look forward to connecting!  

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