Infertility is defined as the inability of a sexually active woman to conceive without contraception for more than one year. About 25% of couples are unable to conceive after one year of marriage, of which 15% will seek treatment and 5% will reluctantly accept infertility as the end. Infertility affects both men and women, and the male factor accounts for about 50% of the causes of infertility. If there is only a single factor, the more fertile partner can compensate for the less fertile partner, so the presence of reduced fertility in both partners usually leads to infertility. Causes of reduced fertility in men include congenital and acquired genitourinary tract malformations, reproductive tract infections, elevated scrotal temperature (varicocele), endocrine disorders, genetic defects and immunologic factors. However, no cause can be found in at least 44% of patients (idiopathic male infertility), who have no relevant medical history, normal physical and endocrine examinations, and semen analysis showing oligospermia, weak spermatozoa, and dyszoospermia. Often, these abnormalities occur together and are referred to as oligozoospermia, weak spermatozoa, and teratozoospermia (OAT). Table 1 summarizes the major causes of male infertility. Table 1 Etiological statistics of 7057 male infertility patients Sexual dysfunction 1.7% Genitourinary tract infection 6.6% Congenital anomalies 2.1% Acquired disorders 2.6% Varicocele 12.3% Endocrine disorders 0.6% Immunological factors 3.1% Other anomalies 3.0% Idiopathic abnormalities of the seminal fluid (OAT syndrome) 75.1% or unknown causes When the period of infertility is longer than 4 years without contraception, the monthly rate is 0.0%. When contraception is not used and fertility is not achieved for more than 4 years, the monthly pregnancy rate is only about 1.5%. Currently, women in many Western countries do not consider having children until they have completed their education and are working, yet a woman’s fertility at age 35 is only about 50% of that at age 25, dropping to 25% at age 38, and possibly dropping further to less than 5% over age 40. In assisted reproduction, the woman’s age is the most important factor affecting the success rate. Recommended protocols When classifying infertility, both partners should be examined at the same time; when diagnosing and treating male infertility, the fertility of the female partner must be taken into account, as it may determine the final outcome. Urologists and male specialists should examine all infertile male patients for genitourinary malformations, to clarify the causes of the decline in semen quality, which must be made before appropriate treatment (medication, surgery, or assisted reproductive technology) is initiated. Diagnosis.