ABSTRACT Risk-Taking, Digit Ratio and Circulating Testosterone Vlad Irimia Using evolutionary psychology as a theoretical framework, the paper argues that extreme sports act as a vehicle for men to display social status and genetic fitness to prospective mates. Despite lacking an apparent utilitarian outcome, the behavior of skydivers can be seen as a costly signal given that parachute jumping requires substantial courage, athleticism, coordination, mental fortitude, and a willingness to take risks, all of which are characteristics deemed attractive to the opposite sex. We explore the biological basis of physical risk-taking by measuring skydivers’ fluctuating testosterone levels and consequently, demonstrating an increase in their salivary testosterone concentrations following the act of parachuting. This hormonal change suggests that successfully engaging in a physical risk triggers an endocrinological response in men that is similar to the one triggered during competition. Testosterone is largely responsible for our species’ sexual dimorphism, entailing that testosterone may also be responsible for the colossally unbalanced sex ratio in extreme sport participation. Developmental testosterone exposure measured through two biomarkers (second-to-fourth digit ratio and facial width-to-height ratio) were also taken into account in relation to extreme sport engagement. Finally, a survey examining the Sociosexual Orientation Inventory, Life History Theory as well as other psychological variables were included in the study. These scales are nomologically related to the theoretical foundation of the present research. A better understanding of what drives extreme sport engagement provides marketing practitioners and scholars a useful theoretical framework for understanding similar types of consumptions.