Spermatozoa with a total viability of less than 20% or less than 5% of a-grade spermatozoa are considered to be in severe cases of weak spermatozoa. Weak spermatozoa refers to low sperm motility, i.e., the range of routine semen tests that show less than 25% of a-grade spermatozoa or less than 50% of the total number of a+b-grade spermatozoa are considered weak spermatozoa. The criteria for severe weak spermatozoa are sperm motility of less than 20% or the percentage of a-grade sperm is less than 5%. In severe spermatozoa, the spermatozoa are less viable and lose the ability to fertilize the egg, which can eventually affect pregnancy and even lead to infertility. Therefore, it is recommended to consult a doctor for diagnosis or symptomatic treatment of spermatozoa in a timely manner and consult a regular medical institution to avoid delay or even aggravation of the condition.