Ovarian expression of BRCA1 and BRCA2 was significantly lower in the endometriosis group, compared with controls [0.12 ± 0.06 vs. 0.22 ± 0.09 (p = 0.045) and 0.16 ± 0.08 vs. 1.26 ± 0.52 (p = 0.001), respectively]; but Rad51 and ATM expression levels were comparable in the two groups [0.38 ± 0.11 vs. 0.51 ± 0.16 (p = 0.621) and 0.79 ± 0.13 vs. 0.76 ± 0.26 (p = 0.526), respectively]. The gene discussed is ATM; the disease is endometriosis.