This umbrella review synthesizes evidence from high-impact systematic reviews, meta-analyses, and scoping reviews addressing gender-based violence, labor discrimination, and cognitive-behavioral differences. It evaluates the global prevalence of intimate partner violence (IPV), femicide, and workplace sexual harassment/violence, as well as mental health consequences and gender-related economic gaps. A methodological appraisal using AMSTAR-2 is applied, alongside an interpretive and bounded reading of ROBINS-I where appropriate, and a GRADE-based certainty rating to estimate confidence in the body of evidence. Results indicate a persistent motherhood wage penalty (approx. 3.6-3.8% per child), a global lifetime IPV prevalence of 27%, and a pooled prevalence of workplace sexual harassment/violence in women close to 26%, with strong heterogeneity by region and occupation. In hiring, biases align systematically with the gender composition of jobs, and in leadership the glass cliff pattern persists. The synthesis integrates micro-, meso-, and macro-level mechanisms and proposes a policy implications matrix aligned with the certainty of the evidence.