Then, we excluded the study conducted by Qiu et al. and found that serum leptin of patients with AIS was significantly lower when compared with healthy controls (WMD = − 0.95, 95% CI − 1.43 to − 0.48, p < 0.0001), and the six sets of results showed no heterogeneity (p = 0.50, I2 = 0) (Fig. 3). Here, LEP is linked to androgen insensitivity syndrome.