Sperm with small head and malformation can be related to various reasons such as infection, varicocele, heredity, environmental factors or physical factors. 1. Infection: when the reproductive glands and reproductive tract have pathogenic microorganisms such as Mycoplasma, Chlamydia trachomatis infection can cause high sperm deformity rate, pathogens are mostly infected with the urethra, epididymis and prostate, resulting in the destruction of sperm cell membranes, so that the sperm head and tail are deformed, thus affecting the reproductive function. 2. Varicocele: under varicocele, the blood circulation of testis is abnormally altered, which has the effect of local temperature increase, blood stagnation and metabolite stagnation, thus causing the rate of malformed sperm to increase. 3. Heredity: when there are malformed sperm in the semen and the cause is unknown, it is considered to be related to heredity, such as the micro-deletion of the normal Y chromosome, which can lead to sperm malformation. 4. Environmental factors: the body and environmental chemicals (such as chromium, lead and other metals or pesticides such as organophosphorus pesticides, etc.) contact, can damage the reproductive function, resulting in damage to the reproductive system, sperm deformities increase and sperm count decrease. 5. Physical factors: such as radiation, radiation, ionization, high temperature, laser and other physical factors can reduce the number of spermatozoa in the testes and epididymis and increase the rate of malformation. When malformed spermatozoa are found, it is recommended to try to find out the cause of the disease and treat the disease under doctor’s guidance. Men should also quit smoking and drinking to stay away from high-risk factors.