The fertility of men over the age of 80 will decline to a certain extent, but if the quality of sperm and the function of the reproductive system are normal, they are usually still fertile. Sexual function usually declines after the age of 60, and the quality of sperm will also gradually weaken, which is manifested by a gradual decrease in the production of sperm compared with that of younger men, an increase in the number of immature and aged sperm, a decrease in the survival rate of sperm, and an increase in the rate of abnormalities, all of which will have a certain impact on fertility and lead to a gradual decline in male fertility. However, there is no obvious limit to the termination of male fertility. If a man is in relatively good health at the age of 80 or above, with normal functioning of the reproductive system and normal functioning spermatozoa, he is generally still fertile. Therefore, when a man is over 80 years old, he can go to the hospital to check the quality of his sperm, the function of his reproductive system and his physical condition, so that the doctor can make a clear diagnosis as to whether or not he still has the ability to procreate.