In this essay I will be addressing the various efforts of American sociologists to investigate and regulate their field’s relationship to biology over a period of some hundred years. I will be looking at the field’s internal development as well as how it has reacted to various bigger social and historical events. We will particularly look at episodes of “nature vs. nurture” controversy as we follow sociology’s changing self-definition over time. This means we will be tracking the field from its beginning in the early twentieth century to the present, paying special attention to sociology’s encounters with biology, including the arrival of the neo-Darwinian or Modern Synthesis in the 1940s, the challenge of sociobiology in the 1970s, and various later efforts to “bring in Darwin” as the answer to sociology’s academic identity problem. But “biology” also relates to sociology’s role in regard to such things as IQ testing, race differences, and eugenics, and more recently initiatives such as sociogenomics, at the precarious intersection between scientific and moral/political concerns. It is even unclear if one can separate a social science’s academic identity from its sociopolitical role. What is clear, however, is that sociology (with other social sciences) has experienced a number of collectively felt crisis situations during the past hundred years.