The five types of male infertility are: "heaven," fistula disease, tendon, timidity, and transformation. "Heaven" refers to "congenital eunuch," generally indicating congenital defects in male external genitalia or testes, as well as incomplete development of secondary sexual characteristics. "Fistula disease" refers to the inability to retain semen, often leading to involuntary emission. "Tendon" refers to the removal of the penis or testicles. "Timidity" refers to impotence. "Transformation," also known as "human anomaly," is similar to intersex conditions, commonly referred to as "yin-yang people."