Men may generally lose their fertility when they reach around 70~80 years of age, but there are a few men whose fertility can last until they are over 80 years old, depending on a variety of reasons such as individual’s physical condition, quality of sperm and lifestyle. As men grow older, their fertility will slowly decline. Generally, by the age of 70 to 80, the level of androgens and the quality of sperms are no longer able to meet the requirements of fertility, and even if they are fertile, the sperms may not be able to unite with the eggs, and in general, the fertility of males lasts for a longer period of time than that of females. To determine whether a man is fertile or not, he should go to the hospital for semen analysis, blood tests for sex hormone levels, develop good habits, exercise properly, do not stay up all night, and quit smoking and drinking.