MedicalResearch.com Interview with: Carla Aimé PhD Institute of Evolutionary Sciences of Montpellier France MedicalResearch.com: What is the background for this study? What are the main findings? Response:  In all human populations, regardless of environmental and socioeconomic conditions, menopause occurs in women well before the end of their expected lifespan. Conversely, extensive post-reproductive life-span is rare in other species; except in some cetaceans. Evolutionary theory predicts that menopause and extensive post-reproductive lifespan should emerge and persist in populations only if it is advantageous for gene transmission. Identifying this advantage is a long-standing issue, and some hypotheses has already been suggested by other researchers. However, testing these hypotheses about the emergence of menopause is difficult, in particular because menopause exists today in all human populations. It is thus not possible to measure in real life the evolutionary advantage related to menopause by comparing gene transmission of women who stop reproduction and women who don't stop reproduction. Here, we used computer simulations to overcome this difficulty by modeling the emergence of menopause in simulated human populations. The main finding were the following : - Physiological constraints are not required for menopause to emerge. - The increasing cost of reproduction with age cannot explain menopause. - Grandmothering is part of the process leading to menopause : stopping reproduction allow reallocating resources to existing children and grand-children, thus leading to increase gene transmission via increased fertility of children and survival of grand children - Cognitive resources are also important. Indeed, cognitive abilities allow accumulation of skills and experience over the lifespan, thus providing an advantage for resource acquisition. These surplus resources can then be used to increase the number of offspring or be transmitted to existing offspring and grandoffspring. Stopping reproduction during aging allows allocating more resources to assist offspring and grandoffspring, thus increasing children’s fertility and grandchildren’s survival. (more…)