Hazem NM, et al. - Researchers tried to find out the effect of cannabinoid receptors Type 1 and Type 2 mRNA expression in mature vs immature spermatozoa from fertile and infertile males. A total of 100 individuals were included in this study. Individuals were divided into fertile (n = 50) and infertile groups (n = 50). They obtained fresh semen samples. Computer-assisted semen analysis and acrosin activity tests were performed. The results showed that cannabinoid receptors 1 (CBR1) expression was significantly related to variation in sperm morphology, and CBR2 was significantly related to both sperm morphology and linearity index in mature spermatozoa. The results of this study indicated that CBR1 and CBR2 mRNA expression may closely direct sperm maturation at different steps of the reproductive process.