Genogram Rules
The 15 essential rules for creating clinically accurate genograms. Based on McGoldrick, Gerson & Petry's standardized notation system.
Why Genogram Rules Matter
Without standardized rules, a genogram created by one clinician cannot be reliably interpreted by another. The entire value of the genogram as a clinical tool depends on shared conventions: when you see a square, you know it represents a male; when you see a zigzag line, you know it indicates conflict. This shared language is what makes genograms useful across treatment teams, supervisory sessions, case consultations, and published research.
The standard notation system used today was developed and refined by Monica McGoldrick, Randy Gerson, and Sueli Petry over several decades of clinical work and academic collaboration. Their definitive reference, Genograms: Assessment and Treatment (4th edition, 2020), published by W.W. Norton, is the most widely adopted standard in family therapy training programs worldwide. These rules ensure that genograms function as a universal clinical language rather than personal shorthand.
The McGoldrick-Gerson Standard
McGoldrick, Gerson & Petry (2020) established the notation conventions that are taught in virtually every family therapy training program. Their system covers symbol shapes, relationship line types, generational layout rules, and annotation standards. When clinicians refer to "standard genogram notation," they are referring to this system. Adherence to these rules is what allows a genogram created in New York to be read accurately by a therapist in London or Tokyo.
The 15 Essential Genogram Rules
Based on the McGoldrick-Gerson-Petry standardized notation system
Males Are Squares, Females Are Circles, Nonbinary Uses Diamonds
The most fundamental rule: males are represented by squares, females by circles, and nonbinary or other gender identities by diamonds. This convention is universal and non-negotiable in standard notation.
The Index Person (IP) Has a Double Border
The identified patient or person of focus is indicated by drawing a double border around their symbol. This immediately tells any reader who the genogram centers on.
Deceased Individuals Get an X Through Their Symbol
When a family member has died, draw an X through their square, circle, or diamond. The year of death should be noted beside the symbol.
Generations Are Arranged Horizontally on the Same Row
Each generation occupies its own horizontal level. Grandparents at the top, parents in the middle, children at the bottom. This vertical hierarchy is essential for readability.
Oldest Siblings on the Left, Youngest on the Right
Within each sibling group, birth order reads left to right, with the firstborn on the far left and the youngest on the far right. This convention ensures consistency across all genograms.
Marriages and Partnerships Connect with Horizontal Lines
A horizontal line connects two partners. The male is traditionally placed on the left and the female on the right, though this convention is flexible in modern practice.
Children Descend Vertically from the Couple Line
A vertical line drops from the horizontal couple line, then branches to connect to each child. Children hang from this line in birth order (left to right).
Structural Relationships Use Specific Line Patterns
Marriage is a solid horizontal line, separation adds one diagonal slash, divorce adds two diagonal slashes, and cohabitation uses a dashed line. These structural lines show legal/formal relationship status.
Emotional Relationships Use Colored or Styled Lines
Emotional relationships are shown between any two people: close (double line), enmeshed (triple line), distant (dotted line), conflictual (zigzag line), cutoff (line with break). These are distinct from structural lines.
Twins Connect to the Same Point on the Descent Line
Identical twins connect to the same point with a horizontal bar between them. Fraternal twins connect to the same point without the bar. This distinguishes twin type at a glance.
Miscarriages and Stillbirths Have Specific Smaller Symbols
A miscarriage is shown as a small filled circle or triangle, a stillbirth as a full-sized symbol with an X, and an abortion as a small symbol with an additional line. These are always smaller than standard symbols.
Adoption Uses Dashed Lines to Adoptive Parents
Adopted children connect to their adoptive parents with dashed lines and to their biological parents (if known) with solid lines. This visually distinguishes biological from legal relationships.
Include at Minimum Three Generations
A clinically useful genogram must include at least three generations: the index person, their parents, and their grandparents. This minimum allows pattern recognition across generational lines.
Include Dates: Birth, Death, Marriage, and Significant Events
Every individual should have birth year noted. Deaths, marriages, divorces, and significant life events should include dates. This temporal data is essential for identifying age-related patterns and life cycle transitions.
The Genogram Should Be Readable Left-to-Right, Top-to-Bottom
The overall flow follows Western reading order: older generations at the top, younger at the bottom, older siblings on the left. This ensures any clinician can quickly orient themselves to the family structure.
Common Genogram Mistakes
Errors that compromise readability and clinical accuracy
Mixing Up Structural and Emotional Relationships
Structural lines (marriage, divorce) show legal status. Emotional lines (close, conflictual) show relational quality. These are two separate layers and must not be confused.
Not Aligning Generations Horizontally
When generations are staggered vertically, it becomes impossible to quickly identify who belongs to which generation, defeating the purpose of the genogram structure.
Forgetting the Index Person Marker
Without a double border on the IP, other clinicians cannot tell who the genogram is centered on. This is especially problematic when genograms are shared across a treatment team.
Inconsistent Symbol Sizes
All standard symbols (squares, circles, diamonds) should be the same size within a genogram. Varying sizes can imply importance or hierarchy that does not exist.
Missing Dates and Ages
A genogram without dates loses much of its clinical value. Age at marriage, age at first child, age at death, and age gaps between siblings all reveal important patterns.
Overcrowding Without Spacing
Trying to fit too many people or too much information into a small space makes the genogram unreadable. Use adequate spacing, multiple pages if needed, or focus on the most relevant branches.
How GenogramAI Enforces These Rules Automatically
AI Auto-Alignment and Generational Layout
GenogramAI automatically arranges family members into correct generational rows. Siblings are ordered by birth date, generations are horizontally aligned, and spacing is optimized so your genogram follows Rules 4, 5, and 15 without manual adjustment.
Standard Symbols and Notation
Every symbol GenogramAI places is McGoldrick-Gerson compliant. Squares for males, circles for females, diamonds for nonbinary, double borders for the IP, X marks for deceased, and correctly sized symbols for miscarriages and stillbirths. Rules 1-3 and 10-12 are enforced by default.
Validation and Completeness Checks
GenogramAI validates your genogram against the standard rules, flagging missing dates, unmarked index persons, confused relationship line types, and other common errors before you export. This catches mistakes that even experienced clinicians sometimes make.
Genogram Examples from Our Gallery
Explore related genograms from our collection of 152+ interactive examples
Basic 3-Generation Template
Standard notation with proper symbol placement and generational alignment
Academic/TeachingNuclear Family Symbols Guide
Reference for standard male, female, and relationship symbols
Academic/TeachingRelationship Lines Reference
Complete guide to structural and emotional relationship line notation
Frequently Asked Questions
Who created the standard genogram rules?
The standardized genogram notation system was developed primarily by Monica McGoldrick, Randy Gerson, and Sueli Petry. Their book "Genograms: Assessment and Treatment" (now in its 4th edition, 2020) is the definitive reference for genogram conventions. The system has been refined over decades based on clinical practice and input from the family therapy community.
Are genogram rules the same worldwide?
The McGoldrick-Gerson notation system is the most widely accepted standard internationally, used in clinical training programs, textbooks, and professional practice across countries. While minor variations exist in some regional traditions, the core rules for symbols (squares for males, circles for females), relationship lines, and generational layout are consistent across the field.
Can I modify genogram rules for my specific clinical needs?
While the core symbol and structural rules should remain standard to ensure readability, clinicians often add specialized annotations for their area of practice (e.g., trauma markers, addiction symbols, cultural genogram elements). The key principle is: keep the foundational notation standard so any clinician can read it, and clearly label any custom additions.
How many generations should a genogram include?
The standard rule is a minimum of three generations: the index person's generation, their parents' generation, and their grandparents' generation. However, many clinical situations benefit from four or more generations, especially when tracking intergenerational patterns like addiction, mental illness, or trauma transmission.
What is the most commonly broken genogram rule?
The most common mistakes are confusing structural relationship lines (marriage, divorce, separation) with emotional relationship lines (close, conflictual, enmeshed), and failing to align generations horizontally. These errors make genograms difficult for other clinicians to interpret and can lead to clinical misunderstandings.
Create Rule-Compliant Genograms Automatically
GenogramAI enforces McGoldrick-Gerson notation standards so you can focus on clinical insight instead of drawing conventions.
Try GenogramAI Free