The heritability of rectal cancer is not high, and there is no clear experimental data on the heritability of rectal cancer, which is probably below 10%. There are many characteristics of rectal cancer, including the progression of adenoma, development of rectal cancer or direct development of rectal cancer, which may also be genetically related to the patient. If a patient’s family has an immediate family member with rectal cancer, the patient himself has a high probability of developing rectal cancer. Therefore, once there is an increase in the number of stools or unformed stools, blood in stools or black stools, patients should go to the hospital for examination and treatment in time, especially for patients over 40 years old. You can first check the stool routine to see if there is positive occult blood in the stool, or check the anal finger to see if you can palpate the swelling in the rectum, as well as the need to check the colonoscopy to see if there is a lesion in the rectum and the whole colon.