Li et al. [40] compared fertile men, men with oligoasthenozoospermia, and men with asthenozoospermia and found a significantly lower level (p < 0.05) of TrkA messenger RNA (mRNA) in sperm from men with oligoasthenozoospermia compared with sperm from fertile men and men with asthenozoospermia, suggesting a role for NGF in male infertility. This evidence concerns the gene NGF and Reduced sperm motility.