If a mother has rectal cancer, it may be passed on to her children. Approximately 20-30% of colorectal cancers are clinically associated with heredity. If a first-degree relative has rectal cancer, the risk of developing rectal cancer is higher than the general population. Therefore, if there is a family history of rectal cancer, regular fiberoptic colonoscopy should be done for this group of people so that adenomas can be detected early and removed to prevent the occurrence of rectal cancer. However, the occurrence of rectal cancer is not only related to heredity, but also to the usual diet structure and lifestyle. For example, high protein and high fat intake will increase the chance of rectal cancer, while eating more fresh vegetables and fruits can reduce the occurrence of rectal cancer.