Essentially, women with the faulty BRCA1 or BRCA2 genes have time to consider their options, say researchers from Southampton University, who tracked the cases of 2,733 women aged 40 and younger who were diagnosed with breast cancer over an eight-year period, of whom 338 had the gene mutation. In that time, 651 of the women died from their cancer, but having the faulty BRCA gene didn't make the cancer any more lethal, even 10 years after initial diagnosis.

Around a third of women with the BRCA mutation had a double mastectomy, but it didn't improve their survival chances beyond that of others who had the faulty gene and didn't have surgery.

Strangely, the gene mutation seemed to have a protective effect for the first two years among women with triple-negative breast cancer (where the breast doesn't have receptors for estrogen, progesterone and HER2 proteins).

It's reckoned women with a faulty BRCA1 or BRCA2 gene are around four times more likely to develop breast cancer.