Men's oxidative stress, fluctuating asymmetry and physical attractiveness

Aerobic organisms naturally create reactive oxygen species (ROS) as by-products of energy production. These substances can damage DNA and tissue, and probably are major causes of mutation, ageing and a host of diseases. Oxidative stress occurs when an organism produces an overabundance of ROS relative to ROS-neutralizing antioxidants. In this study, we examined the hypotheses that individual differences in oxidative stress are associated with fluctuating asymmetry and with perceived mate quality. We measured urinary biomarkers of oxidative stress (8-hydroxy-2'-deoxyguanosine (8-OHdG) and malondialdehyde (MDA)) in a sample of healthy, young men and tested their association with fluctuating asymmetry and physical attractiveness. A composite measure of oxidative stress correlated positively with FA and negatively with physical attractiveness (with exposure to toxins, smoking, and their interaction statistically controlled for). Follow-up analyses yielded associations of oxidative stress with both healthy and masculine appearance. No association was mediated by cortisol or testosterone. These findings may yield insights into previously unidentified factors that affect the development of phenotypic features under sexual selection and contribute to the shape of human life histories, and have potential implications for other species as well. (C) 2010 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.