Gender-inclusive pedigree drawing: NSGC 2022, sex vs gender, and clinical practice

Short version. Gender-inclusive pedigree drawing separates two pieces of information that clinical pedigrees have historically conflated: sex assigned at birth, which is relevant for most genetic inheritance calculations (particularly X-linked and Y-linked conditions), and gender identity, which is how the individual identifies. The 2022 NSGC update clarifies that the pedigree symbol (square, circle, or diamond) represents sex assigned at birth, while gender identity is recorded as an annotation. Transgender individuals are drawn with the symbol for their sex assigned at birth and annotated with their gender identity and preferred name. Non-binary individuals are often represented with a diamond and an explicit gender-identity annotation. Intersex individuals and people with differences of sex development are handled through explicit annotations and karyotype where relevant. The goal is accuracy, respect, and preservation of the inheritance-relevant information that makes the pedigree clinically useful.

Why this distinction matters

Pedigrees are clinical documents that inform genetic counselling and risk calculation. For many Mendelian conditions, the relevant variable is the individual's chromosomal complement — whether they carry two Xs, one X and one Y, or some other karyotype. For X-linked and Y-linked conditions specifically, the inheritance pattern is directly tied to the X and Y chromosomes.

Gender identity, by contrast, is the individual's own understanding of their gender — which may align with their sex assigned at birth (cisgender) or differ from it (transgender, non-binary, agender, and other identities). Gender identity is not directly relevant to chromosomal inheritance but is important for everything else in the clinical encounter: preferred name, pronouns, respectful interaction, and the psychosocial dimensions of genetic counselling.

Historical pedigree conventions used squares and circles as though they captured both sex and gender, which was an incorrect conflation. The 2022 NSGC update made the distinction explicit: the shape carries sex-assigned-at-birth information for inheritance purposes, and gender identity is a separate annotated field.

The 2022 NSGC update in practice

Key recommendations from the 2022 update:

• Square and circle represent sex assigned at birth, which is the biologically relevant variable for inheritance calculations.
• Gender identity is recorded as an annotation alongside the symbol, using the individual's preferred terms and preferred name.
• Diamond is used for non-binary individuals and for cases where sex assigned at birth is unknown or unspecified; a gender-identity annotation accompanies the shape.
• Transgender individuals are drawn with the sex-assigned-at-birth symbol and an explicit annotation that identifies their gender identity (for example, "transgender man" next to a circle).
• Intersex individuals and those with differences of sex development are drawn with an explicit annotation describing the specific variation, and karyotype should be recorded where known.
• Legacy pedigrees should be updated where practical, using the 2022 conventions, but historical records remain valid reference points.

The approach preserves the clinical utility of the pedigree — inheritance calculations still work because sex-assigned-at-birth is recorded — while ensuring each individual is represented accurately.

Transgender individuals

For a transgender man (assigned female at birth, male gender identity), the pedigree symbol is a circle and the annotation identifies him as a transgender man with his preferred name. For a transgender woman (assigned male at birth, female gender identity), the symbol is a square and the annotation identifies her as a transgender woman with her preferred name.

The clinical logic: the inheritance implications of X-linked conditions still follow the chromosomal complement. A transgender man with a carrier mother for an X-linked recessive condition has his mother's X risk, calculated against his assigned-female-at-birth chromosomal complement. Reproductive options and cancer risk assessment similarly depend on the biological reality, which the pedigree should represent truthfully.

At the same time, the clinical encounter — the consultation itself, the report writing, the way the individual is addressed — follows the individual's gender identity and preferred name. These are separate facts and can be recorded separately without contradiction.

Non-binary individuals

Non-binary individuals — who do not identify exclusively as male or female — are an increasingly visible part of genetic counselling caseloads. The diamond symbol, used historically for "unknown or unspecified sex," has been repurposed for non-binary gender identity in many contemporary pedigrees, with an explicit gender-identity annotation.

For a non-binary individual, the pedigree should additionally capture the sex-assigned-at-birth or karyotype where it is clinically relevant. For a pedigree where X-linked or Y-linked inheritance is being analysed, not recording the chromosomal complement would compromise the inheritance calculation; the 2022 recommendation is to annotate the sex-relevant biology alongside the non-binary gender identity.

Symbol conventions for non-binary individuals continue to evolve, and some services use alternative conventions (for example, squares-and-circles with modifying annotations rather than diamonds) depending on institutional policy. The key principle is consistency within a service and clarity in the individual record.

Intersex and differences of sex development

Intersex individuals and people with differences of sex development (DSD) have variations in sex characteristics that do not fit typical binary definitions. These include conditions such as complete androgen insensitivity syndrome, congenital adrenal hyperplasia with atypical genitalia, 5-alpha reductase deficiency, and chromosomal variations such as 47,XXY (Klinefelter) or 45,X/46,XY mosaicism.

For DSD, the pedigree should include:

• An explicit annotation describing the specific variation.
• Karyotype where known, recorded in ISCN notation.
• The individual's gender identity where they have expressed one, respected regardless of karyotype.
• Relevant clinical implications for inheritance (some DSDs are inherited and have implications for relatives).

The choice of pedigree symbol depends on clinical context and the individual's preferences, and may be a square, circle, diamond, or a specially noted shape depending on service convention. The accompanying annotation is essential and should not be omitted.

Clinical-relevance flags

A useful practice is to make explicit, on the pedigree, which facts are clinically relevant for the condition under consideration. For an X-linked pedigree, sex assigned at birth matters for inheritance; gender identity matters for the clinical encounter. For a cancer-risk pedigree, age-appropriate screening may depend on the organs the individual currently has, which for a transgender individual may reflect their post-transition anatomy rather than their sex assigned at birth; this should be recorded separately in the clinical note if relevant.

The pedigree is not the only clinical document; decisions about screening, risk-reducing procedures, and reproductive options depend on a fuller clinical picture. The pedigree should be honest about the biology, respectful about the person, and explicit about where further information belongs.

Common concerns and how to address them

• "Do I have to disclose my patient's trans status on the pedigree?" The pedigree should accurately represent sex assigned at birth because that is the inheritance-relevant fact. How detailed the gender-identity annotation is depends on the individual's consent and the clinical setting. Discuss with the patient what they are comfortable recording.
• "Won't this 'out' the patient when the pedigree is shared?" The pedigree is a clinical document shared within the clinical team and under the same confidentiality as the rest of the record. Patients can specify their preferences for how their gender identity is recorded and shared. The 2022 conventions allow for a pedigree that is accurate without gratuitous disclosure.
• "What if the family does not know the patient is trans?" This is a sensitive situation and requires careful counselling. The pedigree used within the clinical team may differ from any version shared with family members. This is not unique to gender identity; other aspects of the medical record are routinely handled with differential disclosure.
• "What if a family member has died and we don't know how they identified?" Record sex assigned at birth with a note that gender identity is not known; do not assume cisgender identity by default but do not fabricate gender identity either.

How Evagene supports this

Evagene records sex assigned at birth and gender identity as separate structured fields on each individual on the pedigree. The pedigree symbol is derived from sex assigned at birth, ensuring inheritance calculations work correctly for X-linked, Y-linked, and sex-specific conditions. Gender identity is recorded as a labelled annotation and included in the rendered pedigree according to service configuration and individual preference.

The 2022 NSGC conventions are built into the default symbol set. Transgender individuals can be recorded with their sex assigned at birth, gender identity, and preferred name; non-binary individuals are represented with the diamond symbol and an explicit gender-identity annotation; intersex individuals are handled through explicit annotations and optional ISCN karyotype recording.

Inheritance analysis — Mendelian calculations, BRCAPRO/MMRpro/PancPRO, X-linked calculations — uses the sex-assigned-at-birth field as the biologically relevant variable, while the clinical narrative and AI-drafted reports respect the individual's gender identity and preferred name. This separation of concerns keeps the pedigree clinically accurate and the patient interaction respectful.

PDF, PNG, and SVG exports preserve the gender-inclusive conventions, and the embeddable viewer renders them consistently in patient portals, research dashboards, or EHR integration layers.

Frequently asked questions

Related reading

• NSGC pedigree notation
• ISCN pedigree symbols
• How to draw a pedigree chart
• Three-generation family history
• Pedigree drawing software
• Clinical genetics pedigree tools