2008) contrasting reports exist on levels of leptin in endometriosis patients, showing no difference, an increase or a decrease. Markedly increased level of leptin mRNA and protein in rats with endometriosis was reported (Wu et al. 2002) but other reports did not support this proposal and concluded that serum leptin is unchanged in endometriosis (Gungor et al. 2009). This evidence concerns the gene LEP and endometriosis.