According to statistics, the incidence of infertility among couples of childbearing age is currently 10% nationwide, with a total of more than 40 million people, of whom, about 40% are men, while 80% of male infertility patients are young adults between the ages of 25-35. Young men who understand some simple fertility knowledge and self-testing methods can effectively self-examine whether they are at risk of infertility. With some regular self-examination, maintain good health and future family happiness. The causes of male infertility are mainly focused on genetics, sex hormone abnormalities, varicocele, reproductive tract infections, cryptorchidism, poor living habits and external pollution. If you gently touch along the spermatic cord from top to bottom and find a large worm-like soft and tortuous mass in the scrotum, you should be aware that this may be varicocele. It will make the testicular temperature rise and the stagnation of venous blood affects the testicular metabolism, thus interfering with sperm production and causing a decrease in semen quality. If there is swelling and pain in the testicle, and the testicle gradually shrinks after relief, it may be testicular torsion or post-inflammatory testicular damage atrophy. This is often accompanied by irreversible damage to the spermatogenic cells. If the testicle fails to descend into the scrotum and remains in the abdominal cavity, it is called cryptorchidism. The high temperature in the abdominal cavity is not conducive to sperm production and the risk of testicular malignancy is greatly increased. Semen can also partially reflect fertility, so a semen analysis is also necessary. It is best to go to a regular public large hospital male department or reproductive center for testing if you do not ejaculate for 3-5 days. Normal semen is off-white or slightly yellowish. If it appears pink or red, it is hemorrhagic semen. The normal semen volume is 2-6 ml, more than 7 ml is too much, less than 2 ml is too little, and less than 1 ml is too little, which is very likely to lead to infertility. Generally, semen will change to liquid in 15-30 minutes after ejaculation. If it cannot change its form after more than 60 minutes, it is clinically called semen non-liquefaction, which is also a cause of infertility. The World Health Organization stipulates that the standard value of sperm density is 20 million/ml. If the test value is greater than 20 million, it is normal; if it is lower than the standard value, it is oligospermia, and oligospermia will probably lead to infertility.