I examine the ways in which the theological and philosophical debate surrounding transhumanism might profit by a detailed engagement with contemporary biology, in particular with the mainline accounts of species and speciation. After a short introduction, I provide a very brief primer on species concepts and speciation in contemporary biological taxonomy. Then in a third section I draw out some implications for the prospects of our being able intentionally to intervene in human evolution for the production of new species out (...) of Homo sapiens. In a fourth section Account of Human Nature? And Where Does This Leave Transhumanism?”) I bring in the debate over the proper relationship between biological and theological conceptions of human nature, laying out the major options available and considering their possible implications for our understanding of transhumanism. In a fifth section several concrete examples are drawn out pertaining to particular subdisciplines within theology. I conclude by briefly laying out some suggestions for future work, focusing on tasks that theologians specifically ought to pursue. (shrink)