Did you know that a person’s chance of developing breast cancer could be affected by the genes they inherit from their parents? Here’s why. Our bodies are made up of trillions of cells, each of them containing DNA. DNA acts as the cell’s instruction manual, and determines how it will function. Within every piece of DNA there are thousands of genes that help it do this. You have two of every gene – one from your mum, and one from your dad. Your exact mix of genes is unique. Unless you have an identical twin, nobody has the same set of genes as you. Sometimes genes can contain faults. Genetic specialists call these mutations. In some cases, a fault doesn’t have any effect. However, it could cause a cell not to function quite as it should, or be more likely to behave oddly in the future. Scientists have identified faults in certain genes that can increase the risk of breast cancer. These include the BRCA1 and BRCA2 genes. These faulty genes won’t definitely cause breast cancer, but they do increase the chance for it to develop. A faulty BRCA1 or BRCA2 gene can be passed down from generation to generation, just like any other gene. If one of your parents carries a faulty version of the gene, there’s a fifty percent chance that they will pass it on to you. Likewise, if you inherited this single faulty gene, there’s a fifty percent chance that you’ll pass it on to each child that you have. If you didn’t inherit the faulty gene, there is no chance that you can pass the fault on to your own child. Breast cancer genes cannot skip generations. So what does this mean? People who have a family history, and are estimated to have at least a one-in-ten chance of carrying a faulty gene, can have genetic testing to check for this. Genetic tests can sometimes find faulty genes, and help individual family members find out whether or not they are at increased risk. However, it’s important to remember that most breast cancers are not caused by inherited genes, and are not related to a family history. You can always speak to your doctor to see if you should be tested.