[Variation trend of male fertility and semen parameters]

In recent years, the variation trend of male fertility and semen parameters has aroused much academic controversy and become a focus of public attention. For the assessment of male fertility, female pregnancy is regarded as a gold standard, but semen parameters are commonly used as surrogate or indirect evidence in clinical practice and laboratory research. The reference range of se- men parameters being used in China is based on the WHO recommended data and lacks the specific reference value for healthy Chinese men. No definite conclusion has yet been derived from studies at home and abroad on the general variation trend of semen parameters worldwide, but many researchers agree on the decline of semen quality in some areas of the world. Long-term continuous prospective studies are needed for the evaluation and prediction of the general variation trend of semen quality.