My Mother and Grandmother Both Had Breast Cancer

Your mother had breast cancer, your grandmother had breast cancer, and you want to know two things: what that does to your own chances of getting breast cancer, and what it triggers when an insurance form asks about your family. They are different questions with different answers, and running them together is what makes this frightening. Take them apart and it becomes manageable.

On the medical side: two affected generations on the same side of the family is a real reason to talk to your GP, but it does not, by itself, mean a faulty gene runs in the family. Breast cancer is common, and two relatives can be affected by chance. What the NHS does with your family history is a risk assessment, not an automatic gene test — and two generations affected may be exactly the pattern that meets the threshold for that assessment.

On the insurance side, the threshold is a different one, and often a narrower one. Many application forms ask only about parents, brothers and sisters, so a grandmother can fall outside the question altogether. This page keeps the two thresholds apart — what triggers a clinical referral, and what you actually have to put on a form — because they do not move together.

Does two generations mean a faulty gene?

Usually not. Most breast cancer is not caused by a single inherited fault, and because the disease is common, two relatives across two generations can be affected without any inherited gene being involved. That is genuinely reassuring, and it is the correct starting point rather than wishful thinking.

What raises the suspicion of an inherited cause is not the count alone but the pattern around it. A young age at diagnosis, cancer in both breasts, breast cancer in a male relative, ovarian cancer alongside the breast cancer, or Ashkenazi Jewish ancestry all push the picture towards something worth investigating. If your mother and grandmother were both diagnosed young, that carries more weight than two diagnoses in later life. This is the same logic a reader works through after a mother's breast cancer at 42, where the early age is the detail that changes the conversation.

The "same side" detail matters more than the number

For a hereditary pattern, the cancers need to sit on the same side of the family. Your mother and her mother — your maternal grandmother — are on the same side, and that is the arrangement that counts toward an inherited risk. A mother on one side and a grandmother on the other is a weaker signal, because a single fault is passed down one lineage, not assembled from both.

The closeness of the relative matters too. Your mother is a first-degree relative; a grandmother is second-degree. Genetics services weigh first-degree relatives more heavily, but a second-degree relative on the same side still adds to the picture, especially when combined with a first-degree one. So "mother and maternal grandmother" is a stronger pattern than either alone — which is precisely why it can reach the referral threshold when a single relative might not.

The NHS genetics referral threshold

Whether your history warrants a referral is decided against published thresholds. In England and Wales, the National Institute for Health and Care Excellence sets criteria based on how many relatives were affected, how closely related they are to you, their ages at diagnosis, and whether the cancers sit on the same side. Your GP works through this with a family tree, often using a checklist, and refers you if you cross the line.

Source: National Institute for Health and Care Excellence (NICE), guidance on familial breast cancer risk assessment and management, nice.org.uk.

A crucial point about what a referral is: it leads to a risk assessment, not automatically to a genetic test. Genetics services sort people into broad risk categories — close to the general population, moderate, or high — and only a minority go on to be offered testing, usually where the pattern is strong or a fault is already known in the family. Many people who are referred are reassured, or moved into enhanced screening, without any test at all. Being referred is not the same as being told you carry something.

What a referral actually leads to

The practical outcomes of a referral are the useful part. Someone assessed as moderate or high risk may be offered breast screening earlier and more often than the general programme provides, sometimes starting in the forties and sometimes by MRI as well as mammography. Where the family pattern justifies it, a genetics appointment may follow, and in some cases a test for a known family fault. In others, the outcome is straightforward reassurance and a return to standard screening.

The reason all of this is worth doing comes down to detection. Breast cancer is one of the more survivable common cancers in England when it is found early, and the whole point of enhanced screening is to catch anything at that early stage. Family history sets the level of surveillance; catching a cancer early is what surveillance then buys you.

It is worth being clear about what these figures do and do not tell you. Survival statistics describe groups of people who have already been diagnosed, sorted by how far the cancer had spread when it was found. They are not a prediction about a well person with a family history, and they cannot tell you whether you personally will ever develop breast cancer. What they establish is the direction of the argument: the stage at which a cancer is caught moves the outlook a great deal, which is exactly why the surveillance a referral can unlock is worth having. A raised risk that leads to earlier, closer screening is a manageable thing, not a sentence.

Source: NHS England, National Disease Registration Service, Cancer Survival in England, cancers diagnosed 2018 to 2022.

The insurer's threshold is a different threshold

Here is where people over-worry. An insurance application does not use the NHS referral criteria. It asks its own, usually narrower, family-history questions — and a great many forms ask only about parents, brothers and sisters, sometimes only where they were diagnosed before a certain age. A grandmother is a second-degree relative and can fall entirely outside what the form is asking.

So the first task with a form is to read what it actually asks, not what you fear it might ask. If it asks about parents and siblings only, you answer about your mother and not about your grandmother, because the grandmother is outside the question. Your duty, under the Consumer Insurance (Disclosure and Representations) Act 2012, is to take reasonable care not to misrepresent the answers to the questions put to you — it is not a duty to volunteer everything in the family tree. Answer what is asked, accurately; do not pad it with information the insurer did not request, and do not leave out a parent the form does clearly ask about.

Family history and a genetic result are two different things on a form

Keep these separate, because insurers treat them completely differently. Family history — what your relatives were diagnosed with — can be asked at any level of cover, and where a form asks, you answer. A predictive genetic test result is the opposite: it cannot be asked for or used, under the Code on Genetic Testing and Insurance, with a single exception for Huntington's disease above £500,000 of life cover that does not touch breast cancer at all.

Source: HM Government and the Association of British Insurers, Code on Genetic Testing and Insurance, published on gov.uk.

So if you were tested and carry a predictive result for a breast cancer risk gene, that result stays off the application. What is disclosable, if asked, is medical fact — a diagnosis, surgery, treatment you yourself have had. A newer question is whether a risk score built from many small genetic markers even counts as a "genetic test" for these purposes, which is not fully settled; we look at that in whether a polygenic risk score is a genetic test. And if you are thinking about testing that runs in the next generation, the position on a sequenced child is its own topic, covered in your newborn's genome was sequenced, so are they insurable.

Getting cover with this family history

None of this needs to stop you arranging cover, and it should not stop you seeking a clinical assessment either — delaying a referral to protect an insurance application would be the wrong trade, because the predictive result cannot be used against you anyway. On the insurance side, how a family history of breast cancer is weighted varies between insurers, which is a good reason to compare rather than accept the first decision.

When you are ready, you can get life insurance quotes and let an FCA-authorised broker work through the family-history questions against your real circumstances. The broader map of how inherited risk, the odds and the insurance rules fit together is set out in our guide to family history, inherited risk and the odds, which is the place to start if this is one of several things on your mind at once.

Scotland, Wales and Northern Ireland

The insurance rules here are UK-wide: family history can be asked anywhere, and the genetic protection applies across all four nations. What differs is the clinical pathway. NICE criteria are used in England and Wales; Scotland and Northern Ireland run their own genetics services with their own referral arrangements, so the exact route your GP follows may look different even though the underlying aim is the same.

There is also a nation-specific detail on the insurance side worth knowing if you apply in Northern Ireland, where access to a report from your doctor runs under a separate legal regime from Great Britain — set out in why Northern Ireland uses the 1991 Order, not AMRA. It does not change the family-history answer, but it changes some of your rights around the medical evidence behind it.

Frequently asked questions

Does breast cancer in my mother and grandmother mean I carry a faulty gene?

Not necessarily. Most breast cancer is not caused by a single inherited fault, and two affected relatives can occur by chance in a common disease. What raises suspicion is a young age at diagnosis, cancer in both breasts, male breast cancer, ovarian cancer, or Ashkenazi Jewish ancestry alongside it. A genetics risk assessment is what actually quantifies your risk.

When would the NHS refer me to genetics?

NICE sets thresholds based on how many relatives were affected, how closely related they are, their ages at diagnosis, and whether the cancers sit on the same side of the family. Your GP works through that with a family tree. A referral leads to risk assessment, not automatically to a test, and the pathway differs between the four UK nations.

Do I have to tell an insurer about my mother and grandmother?

If the application asks, yes. Family history questions must be answered with reasonable care under the Consumer Insurance (Disclosure and Representations) Act 2012. Most forms ask only about parents, brothers and sisters, so a grandmother may fall outside the question. Read what is actually being asked, and answer that accurately.