A family history of breast or ovarian cancer is one of the main reasons doctors suggest BRCA1/2 genetic testing, particularly when the history involves multiple close relatives, cancer diagnosed at a younger age than typical, breast cancer in a male relative, or both breast and ovarian cancer in the same family line. BRCA1 and BRCA2 are genes that normally help repair DNA damage; inherited mutations in either one raise the lifetime risk of breast and ovarian cancer, and testing is usually preceded by genetic counselling rather than taken as a standalone decision.

When family history is a reason to discuss testing

Testing is more often recommended when the family history includes:

  • Breast or ovarian cancer in multiple close relatives — parents, siblings, or children, especially on the same side of the family
  • Cancer diagnosed at a younger age than is typical for that cancer type
  • Breast cancer in a male relative, which is uncommon and raises suspicion of an inherited cause
  • Both breast and ovarian cancer appearing across the same family line
  • A known BRCA mutation already identified in a relative

A single relative with cancer at a typical age, with no other pattern, is far less likely to warrant testing on its own. This is exactly why genetic counselling is the recommended first step — a counsellor reviews the specific family history in detail to judge whether testing is actually likely to be informative in your case.

What the test actually involves

BRCA testing is done through a blood or saliva sample and checks for specific mutations in the BRCA1 and BRCA2 genes. It doesn't diagnose cancer — it identifies whether you carry a mutation that raises your lifetime risk. A positive result means increased risk, not certainty; a negative result lowers the likelihood of an inherited risk but doesn't eliminate all cancer risk, since most cancers are not linked to BRCA mutations at all.

What a positive result changes

A confirmed BRCA1 or BRCA2 mutation typically leads to a conversation about:

  • Enhanced cancer screening — earlier and more frequent breast and ovarian monitoring than the general population
  • Risk-reducing options, which your doctor and a genetic counsellor would discuss based on your specific situation, age, and family-planning stage
  • Family planning implications — since the mutation can be passed to children, and some risk-reducing surgical options can affect future fertility

How this connects to fertility planning

A positive BRCA result is relevant to fertility planning in a few specific ways. If risk-reducing surgery involving the ovaries is being considered, the timing relative to your family-building plans matters and is worth discussing with both a fertility specialist and your oncology team well in advance — see fertility preservation before cancer treatment for how the preservation window works. Separately, couples who know they carry a BRCA mutation and are planning a pregnancy via IVF sometimes explore preimplantation genetic testing to screen embryos for the mutation before transfer. These are significant, personal decisions best made with a genetic counsellor and fertility specialist together, not on a single conversation.

A family history that fits the pattern above is a reason to talk to a genetic counsellor about whether testing makes sense for you — not a reason to assume the worst, and not something to decide alone without that conversation first.

Frequently asked

My partner has a family history of cancer — should I be tested, or should they?

The person with the family history is usually the one considered for testing first, since the mutation would need to be inherited through their family line. If they test positive, genetic counselling can then clarify what it means for you and any children together.

Does a negative BRCA result mean no cancer risk at all?

No. A negative result for BRCA1/2 specifically lowers the likelihood of an inherited mutation in those two genes, but it doesn't rule out all genetic risk (other, rarer genes can also raise risk) or any cancer risk from non-genetic factors. Your doctor interprets a negative result in the context of your full family history.

If I test positive, does that mean I will develop cancer?

No. A positive result means an increased lifetime risk, not a certainty. Many people with a BRCA mutation never develop cancer, and enhanced screening and risk-reducing options exist specifically to manage that increased risk proactively.

Can a positive BRCA result affect my ability to have children later?

The mutation itself doesn't affect fertility. What can affect fertility planning is if risk-reducing surgery involving the ovaries is being considered as part of managing the increased risk — in which case timing relative to your family-building plans is an important part of the conversation with your specialists.

Should I get tested before or after genetic counselling?

Genetic counselling typically comes first. A counsellor reviews your specific family history to assess whether testing is likely to be informative, explains what different results would mean, and helps you prepare for the decision either way before the test itself is done.