Early Life Stress Modulates Sexual Orientation via Oxytocin and Arginine Vasopressin

Although interactions between environmental and biological factors could affect sexual orientation, little is known about whether early life stress (ELS) may alter sexual orientation by modulating sex hormone levels. We investigated the potential role of two sex hormones: oxytocin (OT) and arginine vasopressin (AVP), in sexual orientation changes induced by ELS. The 89 adult men participants were divided into heterosexual (n = 32) and gay/bisexual (n = 57) groups. Sexual orientation, mental health, and the serum levels of OT and AVP were evaluated. The results indicated that gay/bisexual men experienced more ELS with lower OT and AVP levels. Animal study also demonstrated that ELS resulted in decreased OT and AVP levels and a preference for same-sex in male mice which could be reversed via intraperitoneal OT/AVP treatment. Summarily, individuals with ELS are susceptible to sexual orientation changes and OT/AVP could ameliorate it, which extend the underlying mechanisms of ELS-induced sexual orientation changes.