BDNF and Infertility: Moreover, supporting the idea that a specific genotype may be implicated in infertility related to the disease, lower FF BDNF levels (p < 0.01), lower number of mature oocytes retrieved (p < 0.01) and lower fertilization rates (p < 0.01) were found in endometriosis patients compared to infertile patients not carrying the genotype [36].