Key keywords: Pete Hegseth, high-testosterone military, US Defense Secretary nominee, military combat effectiveness, military medical professionals, testosterone level research, military recruitment policy, military diversity initiatives, conservative cultural rhetoric, US military personnel policy As Donald Trump’s nominee for US Secretary of Defense, Pete Hegseth has sparked widespread controversy in recent weeks for repeatedly advocating for a “high-testosterone military” during public speeches and Senate confirmation hearings. Hegseth claimed that existing diversity, equity and inclusion policies in the US armed forces have driven down average testosterone levels among service members, weakening combat readiness and limiting the military’s ability to respond to global security threats. However, his unsubstantiated claims have been widely debunked by a growing group of military doctors, endocrinologists and public health researchers, who emphasize there is no peer-reviewed scientific evidence linking average service member testosterone levels to overall military operational performance. Experts note that military effectiveness relies on a complex, interconnected set of factors: specialized technical training, cross-team coordination, emotional regulation, strategic decision-making, access to advanced equipment and intelligence support, rather than a single biological hormone marker. Medical professionals also warn that centering military eligibility around testosterone levels would create unfair, discriminatory barriers for thousands of qualified service members, including women, transgender personnel and older veteran staff with decades of frontline or command experience. Many of these personnel hold critical, high-impact roles in cyber operations, intelligence analysis, drone piloting, logistics planning and senior leadership that have no correlation to physical strength or testosterone levels. Additionally, peer-reviewed studies show that people with naturally elevated testosterone levels face higher risks of impulsive decision-making, unprovoked aggression and long-term cardiovascular health issues that can undermine unit cohesion and put fellow service members at risk during high-stakes missions. Critics further point out that Hegseth’s remarks appear tailored to appeal to conservative far-right voter bases rather than address actual gaps in US military readiness. Official Pentagon data from the past 10 years shows that diverse units consistently outperform homogeneous units across nearly all performance metrics, and recent recruitment shortfalls are tied to low service pay, inadequate healthcare for military families and public frustration with decades of unnecessary overseas deployments, not diversity policies. As of press time, Hegseth has failed to provide any peer-reviewed data or military research to support his claims, despite repeated requests from Senate lawmakers and independent medical associations.