A frequent issue in psychiatric clinical practice is the fertility of patients taking psychiatric medications, which primarily involves the teratogenic effects of drugs. The U.S. Food and Drug Administration (FDA) classification of the teratogenic risk of drugs used in pregnant women, which is often cited as evidence-based medical evidence, classifies all drugs into the following five categories. 1. Category A: Controlled studies have shown no teratogenic risk. Controlled studies on human women have failed to find a teratogenic risk for this class of drugs in the first trimester of pregnancy, and the risk of harm to the fetus appears to be negligible; 2. Class B: No evidence of harm to humans. Either animal experiments did not find a teratogenic risk but no human studies were available, or animal experiments showed a teratogenic risk but human studies failed to find a teratogenic risk to the fetus; 3. Category C: Harmful to humans cannot be ruled out. Either animal experiments show that the drug has teratogenic effects or effects on embryos, but there are no controlled studies on humans, or there is neither data from animal experiments nor human studies; 4. Category D: There is positive evidence of harm to humans. There is definite evidence of danger to the fetus, but it can be considered in special circumstances (e.g. when life is at risk); 5. Category X: animal experiments or human studies show that the drug can cause fetal abnormalities, or both animal experiments and human studies show that it can cause fetal abnormalities, and the harm far outweighs the benefit. Among them, the current assessment of the teratogenic risk of psychiatric drugs is shown in the following table. Although the FDA information is clear that it is assessing “teratogenic risk in pregnant women,” many male patients taking psychiatric drugs are concerned about the teratogenic effects of the drugs, so much so that from time to time male patients ask their doctors to stop taking the drugs after marriage, thinking that they will have the same teratogenic risk. Even some specialists have ambiguous perceptions about this and give unreasonable discontinuation advice to male patients who are planning to have children after marriage. In fact, all assessments of the teratogenic risk of drugs are limited to women. Because of the characteristics of male germ cells, it is almost impossible for drugs to cause malformations in male reproduction. First, the mature male germ cell, the spermatozoon, is tadpole-shaped in appearance, with a head end approximately 5 microns long and a tail end (flagellum) approximately 60 microns in total length. A sperm of this size requires a microscope to be seen. The interior of the head end of the sperm is mainly the nucleus of the sperm cell containing 23 chromosomes and basically no cytoplasm. Therefore, it is unlikely that drugs will enter the sperm cells regardless of the medication a man takes. If a drug does enter, it may cause dead sperm or sperm malformation. Second, male sperm cells are extremely active cells that grow and proliferate. From puberty onwards, the sperm cells in the male testes begin to grow, divide, proliferate and mature under the influence and regulation of hormones. From the time the sperm cells begin to proliferate and differentiate to the formation of mature sperm, the cycle is a minimum of 64 days, generally considered to be about 90 days. It is possible that the mature spermatozoa will be released into the vas deferens to become germ cells that will unite with the egg cells to form a fertilized egg after coitus with the reproductive female, but the probability of this is negligible. The number of sperm released by the human male in one ejaculation is extremely large, but only one or two sperm at most can enter the female follicle to fertilize it. Therefore, the male germ cells have a short cycle of proliferation and differentiation and maturation, and unless the drug itself causes the sperm cells to block proliferation and cause male infertility, the drug will not have an effect on whether malformations occur in the male offspring. Finally, there is the advantage of the number of sperm. The volume of semen in a normal male ejaculation is 2-6 ml. The normal semen of a mature male has a sperm count between 60 million and 200 million sperm per ml. The normal standard now used as a semen routine is more than 20 million sperm per ml of semen. Such a large number of sperm that can become united with an egg is generally of good quality. For these reasons, men taking psychiatric drugs are not likely to cause deformities in their fertile offspring, and there is absolutely no need for male patients facing fertility needs to stop taking their medication for this reason. Of course, if the drug factor affects sexual function or causes infertility, this will need to be addressed separately.