Medical Oncologist
CION Cancer Clinics
Drawing the pedigree: your family tree on paper | CION Cancer Clinics
A pedigree is your family cancer history drawn as a diagram of shapes and lines rather than told as a story. This page explains what goes on it, how a counsellor builds it while you talk, and why gaps and approximate memories still make for a useful drawing. At CION Cancer Clinics in Hyderabad, our oncologists review your family history with you and guide you to the right genetic counselling and testing.
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Medically reviewed by Dr. Naresh GunduConsultant Medical Oncologist · MBBS, DNB (Internal Medicine), DM (Medical Oncology, AIIMS) · last reviewed September 2026, next review due September 2027
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On this page
- What is a pedigree, and why does the counsellor draw one?
- The four things recorded for every relative
- The order the counsellor usually works in
- What the basic shapes mean before you see one drawn
- A spoken family history versus a drawn pedigree
- What happens when nobody remembers the details clearly?
- Four things families assume about the pedigree
- Common questions about drawing the pedigree
The short answer
What is a pedigree, and why does the counsellor draw one?
A pedigree is your family tree drawn as a diagram, using shapes and lines instead of a paragraph of text. It lets a genetic counsellor see patterns across generations that are hard to spot from a spoken family history alone, especially once a family runs to twenty or thirty relatives across three generations and two sides.
It is a working document, not a formality
The pedigree is drawn while you talk, and it is redrawn as new details come out. A relative you mention halfway through the conversation, or a diagnosis you remember only when prompted, gets added on the spot. By the end it should look like your actual family, not a tidy diagram made after the fact.
It goes back further than most people expect
A useful pedigree usually covers three generations: yours, your parents', and your grandparents', on both sides of the family. Some conversations go further if an unusual pattern needs explaining, and it is common for a single first appointment to end up covering thirty or more relatives once cousins, aunts and uncles are all included.
It is drawn by hand or on a screen, and both are fine
Some counsellors sketch the diagram on paper as you talk. Others use software that builds the shapes on a screen in front of you. Neither method changes what gets recorded, and you should feel free to ask to see the diagram as it develops rather than waiting until the end.
You do not need to remember every detail perfectly. The counsellor is used to building this from partial, imperfect memory.What goes on it
The four things recorded for every relative
Each person on the diagram carries the same handful of details, not a full biography.
Who they are related to
Lines connect parents, children, siblings and marriages, showing exactly how each person fits into the wider family. If your parents or grandparents were related before they married, say so. A double line marks that marriage, and it can change how a pattern is read.
Whether they had cancer
Shaded shapes mark anyone diagnosed, with the type of cancer noted beside them. Where the organ is known, it matters more than a general word like "stomach trouble" or "a lump".
Roughly what age they were
Age at diagnosis, even an approximate decade, changes how a pattern is read far more than the exact year does.
Whether they are living
A line through a shape marks someone who has died, along with the cause if it is known.
Not sure whether this applies to you?
Ask an oncologistHow it gets built
The order the counsellor usually works in
Starting with you, in the centre
Your own shape goes in the middle of the page, with everyone else added outward from there.
Adding parents, siblings and children first
The closest relatives are drawn before the diagram expands outward to aunts, uncles and cousins.
Working outward on both sides
Your mother's side and your father's side are both mapped, since a fault can come from either one.
Marking every cancer diagnosis found
Each affected relative is shaded and labelled with cancer type and an approximate age.
A first look at the symbols
What the basic shapes mean before you see one drawn
- Square
- A male family member.
- Circle
- A female family member.
- Shaded shape
- Someone diagnosed with cancer, usually labelled with the type.
- Line through a shape
- That person has died.
- Horizontal line joining two shapes
- A marriage or long-term partnership.
- Vertical line below a couple
- Their children, listed in birth order.
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Side by side
A spoken family history versus a drawn pedigree
Told out loud
Drawn as a pedigree
Easy to lose track of who is related to whom
Relationships are fixed and visible at a glance
Patterns across generations are hard to spot
A pattern down one side of the family stands out
Details can be repeated or missed
Each relative appears exactly once
Hard to hand to another doctor later
Can be copied into your file and reused
Filling the gaps
What happens when nobody remembers the details clearly?
Most families cannot answer every question with certainty, and the pedigree does not need them to. "Some kind of cancer, in her fifties, we think" is written exactly like that, with a note that the detail is uncertain, rather than left blank or guessed at more precisely than the family actually knows.
Marking uncertainty is normal, not a weakness
A pedigree with several uncertain entries is still useful. The counsellor reads it knowing which parts are solid and which are approximate, and weighs the pattern accordingly rather than treating every entry as equally reliable. A family with mostly firm dates and one vague entry is read very differently from one where almost nothing is certain, and the counsellor will say so plainly.
A gap can sometimes be filled later
If a detail turns out to matter, the counsellor may suggest a phone call to a relative, or a search for an old record, to firm up one specific entry rather than redoing the whole diagram. Sometimes that single confirmed detail is enough to change whether a pattern looks hereditary or simply unlucky.
One vague relative does not spoil the whole diagram
Families are rarely equally well documented on both sides. It is common for one branch to be remembered in detail, with names, ages and exact diagnoses, while the other is little more than "cancer, we think, on my father's side." A pedigree can hold both kinds of information at once, clearly marked, and the counsellor will read each side accordingly rather than treating the whole tree as unreliable because one branch is thin.
Half-remembered details are still worth mentioning. A vague answer is more useful to the counsellor than no answer at all.Commonly believed
Four things families assume about the pedigree
"I need to bring a family tree I've already drawn myself."
A written list of relatives and diagnoses is enough. The counsellor draws the actual diagram with you, asking questions as they go.
"Only relatives who had cancer need to be included."
Relatives who were never diagnosed still matter, because their place in the family shows how far the pattern does or does not spread.
"If I don't know exact dates, the pedigree is useless."
Approximate ages and decades are normal on a pedigree. Exact dates help but their absence does not stop the diagram from being useful.
"The pedigree is thrown away after the appointment."
It usually stays in your medical record and can be updated at future visits, or shared with a relative who is later referred themselves.
Questions we are asked
Common questions about drawing the pedigree
How many generations does a pedigree usually cover?
Three is typical: yours, your parents' and your grandparents'. It can extend further if the family history suggests a pattern that needs tracing back beyond that.
Do half-siblings and step-relatives belong on the pedigree?
Yes, and they are marked differently from full siblings, since a genetic fault only passes through a biological relationship.
What if I was adopted or don't know my biological family?
Say so plainly. The pedigree is built from whatever biological history is known, and the counsellor will explain what that gap means for interpreting your own risk.
Can I get a copy of the pedigree for myself?
Ask for one. Many people find it useful to keep a copy to share with relatives who may want their own genetic counselling later.
Does the pedigree include cancers that were treated successfully?
Yes. Any diagnosis is recorded regardless of the outcome, since it is the diagnosis itself that matters for the pattern, not what happened afterwards.
What if a relative had more than one type of cancer?
Both are recorded, with separate ages if known. More than one cancer in a single person is a detail that often matters a great deal to the assessment.
Is the pedigree updated at later appointments?
Yes, it should be. A new diagnosis in the family, or a detail that becomes clearer over time, is added at any follow-up visit.
Can two family members' pedigrees be combined?
Often, yes, if they are from the same extended family. Combining them can reveal a pattern that neither person's individual account showed on its own.
Your Specialists
Meet CION's oncologists. Bring your family history or genetic report to them.
Our medical oncologists see people with a strong family history of cancer, arrange genetic counselling and testing where it fits, and plan the checks that follow.
Medical Oncologist
Dr. C. Raghavendra Reddy
MBBS(Gold Medal), DNB(General Medicine), DM(Medical Oncology)(Gold Medal)
Medical Oncologist
Dr. Bharati Devi Gorantla
MBBS, MD(General Medicine), DM(Medical Oncology)(Adyar,Chennai), ECMO, MRCP SCE(UK)
Medical Oncologist
Dr. Owais Mohammed
MBBS, MD (General Medicine), DrNB (Medical Oncology), ECMO, MRCP SCE (Medical Oncology) (UK)
Medical Oncologist
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Sources
- MedlinePlus Genetics — What is a family health history?
- National Cancer Institute — Genetic Testing for Inherited Cancer Susceptibility Syndromes
- Cancer Research UK — What happens when you see a genetic counsellor
This page is general information, not a prescription. Do not change or stop any treatment based on what you read here. If anything is worrying you, contact your own treating team — or call our helpline and we will help you reach the right specialist.
Keep reading
Related pages
Pedigree symbols and how to read yoursUnderstand the diagram once it existsWhat to bring to your first appointmentThe family history you bring becomes this diagramVerifying family cancer history with recordsWhat happens when a detail needs confirmingYour family letter and what to do with itSharing the picture with relatives afterwards
Talk to us
Want help getting your family history ready to draw?
Tell us what you already know about your family and we will help you organise it before your appointment. One helpline serves every CION centre.