The short answer: use a family tree to document ancestry, a pedigree to examine inheritance of a named trait or condition, a genogram to map patterns inside a family system, and an ecomap to map the family's current connections to outside systems. If the question spans internal patterns and external resources, make a genogram and an ecomap as two linked views. Do not force both jobs into one overloaded sheet.
The shapes overlap, but the claims do not. A person-and-relationship diagram becomes useful only after its purpose, evidence source, notation, date, and review boundary are explicit.
The 30-second decision
Ask one question before opening a template:
- Who descended from whom, and what records support that ancestry? Use a family tree.
- How might a specified trait or condition pass through biological relatives? Use a pedigree.
- What relational, health, cultural, or life-event patterns recur inside this family system? Use a genogram.
- Which current organizations, communities, people, and services support or stress the person or family? Use an ecomap.
When two questions matter, keep two views and give them the same preparation date. A genogram can provide the family structure at the center of an ecomap, but the ecomap's school, work, healthcare, housing, legal, faith, friendship, and community links should remain a separate environmental layer.
Family tree: ancestry supported by records
A family tree is a genealogical record. It answers who is related to whom across time and commonly includes names, parentage, partnership, birth and death dates, places, photographs, and source citations. The U.S. National Archives genealogy resources, last reviewed January 15, 2026, direct researchers to records such as censuses, military service files, immigration records, and naturalization records.
That evidence boundary matters. A copied public tree is a lead, not proof. Record the source behind each relationship and flag conflicts instead of resolving them by appearance. A family tree may mention health or occupation, but it is not automatically a clinical record and it should not be read as an inheritance analysis.
Pedigree: inheritance of a specified trait or condition
The National Human Genome Research Institute definition, updated July 31, 2026, describes a pedigree as a chart of how a trait or health condition is inherited through generations. Its key content is biological relationships, the individual or question of interest, affected or carrier status under a printed legend, generations, and relevant dates or ages.
The distinction is purpose, not just geometry. A pedigree should name the trait being followed; an unlabelled fill cannot safely mean “affected.” The 2022 National Society of Genetic Counselors practice resource also clarifies sex and gender representation and carrier-status notation. It does not recommend inventing a new shape for every identity. Clear labels and a current legend are safer than assuming every reader learned the same circle-and-square convention.
The CDC family-health-history guidance, dated September 23, 2024, recommends collecting the condition, age at diagnosis, age and cause of death, and relevant background across close and extended relatives, then updating and sharing the history with a healthcare provider. A pedigree organizes that history; it does not calculate personal risk or establish a diagnosis by itself.
Genogram: patterns inside the family system
A genogram starts with family structure and can add relationship quality, household membership, health information, major events, cultural context, cutoffs, conflict, closeness, and recurring patterns. It is used in settings such as family therapy, counseling, social work, and family nursing.
The 2020 SAMHSA family-therapy guidance describes a genogram as a way to record and interpret family history across genetic, medical, social, and cultural dimensions. It also stresses explaining the diagram's purpose and developing it through a meaningful discussion with the family. That process is a safeguard: a relationship line should record a defined, sourced observation, not turn the preparer's impression into a timeless fact.
Use a genogram when the working question is about patterns across generations. Date sensitive annotations, distinguish reported information from verified records, and keep structural lines readable beneath condition fills and relationship overlays. The companion guide on how to read genogram symbols separates person, structure, condition, and relationship claims.
Ecomap: current support and stress outside the family
An ecomap puts a person, household, or family at the center and maps connections to external systems. Typical surrounding nodes include school, work, healthcare, friends, extended family, housing, transport, faith communities, legal services, recreation, and public agencies. Lines may encode supportive, weak, stressful, or directional relationships, but every style needs a legend.
The original family-medicine description calls an ecomap a picture of a patient's environment and the nature and quality of interactions within it. Later family-caregiving research states the practical split directly: the genogram shows family composition and structure, while the ecomap shows personal and family social relationships.
Use the ecomap for the present environment, not ancestry. Because services, housing, employment, caregiving, and relationship strength change, print an observation date and review it when the plan changes.
Comparison table
| Record | Primary question | Minimum useful content | It cannot establish by itself |
|---|---|---|---|
| Family tree | Who descended from whom? | Names, relationships, dates, places, source citations | Biological certainty, legal status, diagnosis, or inheritance risk |
| Pedigree | How might a named trait or condition be inherited? | Biological relationships, subject of interest, affected or carrier status, generations, legend | Diagnosis, causation, penetrance, or an individual's future outcome |
| Genogram | What patterns appear inside this family system? | Structure, defined annotation layers, dates, informant or record source, legend | That a reported relationship is mutual, permanent, or clinically verified |
| Ecomap | What supports or stresses the person or family now? | External systems, connection quality or direction, observation date, legend | The reason for a relationship, service eligibility, or future availability |
Worked example: the same family, four different deliverables
Suppose a practitioner knows the following: Maya lives with her child; Maya's father and paternal aunt had a named heart condition; Maya reports recurring conflict with one sibling; and the household currently relies on a school counselor, a primary-care clinic, and a neighbor for support.
The family tree records Maya's ancestry and the records supporting each parent-child link. It can omit the support network because that is not the genealogy question.
The pedigree follows the named heart condition through biological relatives. It records ages and ages at diagnosis when known, distinguishes unknown from unaffected, and uses the current pedigree convention. It does not add “high risk” to Maya unless an appropriately qualified assessment supports that conclusion.
The genogram can show the family structure, the heart-history annotation under a defined legend, and Maya's report of sibling conflict with a date and source. It does not turn that report into a finding about blame or abuse.
The ecomap places Maya's household at the center and shows the current school, clinic, and neighbor connections. It can mark which link supplies information, care, transport, or stress. It does not need to repeat three generations of ancestry.
This example uses the same people without pretending the four outputs are copies. Each leaves out information that does not serve its question.
Common failure modes
- Choosing by icon library. A template has circles and squares, so the author calls it a pedigree even though the question is about family-system relationships.
- Combining every layer on one sheet. Ancestry, diagnoses, emotional ties, services, and case actions become unreadable and impossible to update independently.
- Turning unknown into negative. A blank condition mark is read as “unaffected” when it may mean “not asked” or “not documented.”
- Dropping provenance. Sensitive facts and interpretations have no informant, record source, or observation date.
- Using a diagram as proof. A clean drawing can make uncertain parentage, diagnosis, relationship quality, or service availability look settled.
- Copying one notation across disciplines. A line or double mark can carry different meanings in pedigree, therapy, and software-specific legends.
- Treating a living assessment as permanent. An ecomap or relationship overlay becomes stale while the date remains invisible.
Privacy and the next step
These diagrams can expose health conditions, adoption, fertility, death, conflict, violence, substance use, immigration status, housing, and information about relatives who did not consent to the record. Use the minimum necessary detail, follow the rules of the setting, control access, and separate facts from interpretations. For personal family health history, the U.S. Surgeon General's My Family Health Portrait is an example of a tool that keeps the entered information in a file controlled by the user rather than transmitting it to a government server.
Before drawing, write a five-line specification: question, audience, evidence sources, notation and legend, review date. Then choose the format from the decision rule above. For a diagram that may need separate genogram, pedigree, and ecomap views, use ChatDiagram's genogram maker. Keep uncertain facts visibly uncertain and have the responsible professional or record owner review the final sheet.