In endometriosis, FF exhibits elevated levels of nitric oxide (NO), iron, cadmium, and lead, alongside diminished antioxidant enzymes such as superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), and glutathione (GSH)—a milieu associated with decreased fertilization rates and impaired blastocyst development [4,17]. The gene discussed is CAT; the disease is endometriosis.