According to the meta-analysis from 4 studies [10, 12, 13, 17], FSH among those subjects recovered from COVID-19 was 0.09 mIU/mL less than those without COVID-19 (overall MD − 0.09; 95% CI − 0.32, 0.15; p = 0.26 I2 = 26%) (Fig. 3). The gene discussed is BRD2; the disease is COVID-19.