Genetic testing for inherited disease-causing changes in breast cancer genes is currently limited by guidelines that determine who is eligible.  Testing breast cancer patients in England was updated in April-2022 making it more widely available, including all women diagnosed under 40years, except those with low grade cancers-(grade-1). However, this exception was recently dropped, apparently to simplify testing. We have assessed the likelihood of faults in BRCA1/2 in grade-1 versus grade-3 oestrogen receptor positive breast cancer showing much higher rates in older women (40-49 years) with grade-3 disease-(6.9%) than those <40 with grade-1-(1%) confirming the illogicality of the decision to test younger grade-1 over older grade-3.  (By Professor D Gareth Evans, https://jmg.bmj.com/content/early/2024/07/25/jmg-2024-110183 )