In the light of the opportunities presented by the Sustainable Development Goals (SDGs) debate is being reignited to understand the connections between human population dynamics (including rapid population growth) and sustainable development. Sustainable development is seriously affected by human population dynamics yet programme planners too often fail to consider them in development programming, casting doubt on the sustainability of such programming.
Same-sex sexual behavior has been extensively documented in non-human animals. Here we review the contexts in which it has been studied, focusing on case studies that have tested both adaptive and non-adaptive explanations for the persistence of same-sex sexual behavior. Researchers have begun to make headway unraveling possible evolutionary origins of these behaviors and reasons for their maintenance in populations, and we advocate expanding these approaches to examine their role as agents of evolutionary change.
