Background: This study investigated the influence of EMP (electromagnetic pulse), S-HPM (S-band high power microwave) and X-HPM (X-band high power microwave) on the offspring sex ratios and its mechanism. Methods: X and Y sperms isolated from mature cow, primary sertoli and germ cells isolated from Wistar rats, and Kunming mouse were exposed to EMP (6×104V/m), S-HPM (100 mW/cm2) and X-HPM (100 mW/cm2) for 4min respectively. Sperm dynamic analysis systerm detected sperm motility. Flow cytometry determined cell apoptosis. Pathological changes were observed by Light and electron microscope. Real-time PCR and western blot analyzed gene expression. Radioimmunoassay detected the level of secreted cytokines in culture medium. Results: After whole-body EMP radiation of male mice, the male offspring ratio decreased significantly than control group. Both X and Y sperm were injured after radiation, especially for the sperm head. Acid phosphatase content of sperm apical body decreased. The expression of TNFα, IL-6 and IL-1β up-regulated, memberane malonaldehyde (MDA) content increased. The expression of AR, SOX9 and WT1 down-regulated. Moreover, the ratio of Bax/Bcl-2 and caspase-3 expression increased. Sry expression of germ cells was down-regulated by the cytokines of sertoli cells. The degree of above changes showed as EMP>X-HPM>S-HPM. Conclusion: Electromagnetic radiation could induce a lower ratio of male to female of offspring. The mechanisms refer to the structure and function destruction in head and acrosome of sperm, which may influence the sperm-egg fusion process. Sertoli cells may play an important role in the spermatogenesis process.