DNA allows scientists to determine paternity with over 99-percent certainty using a swab of the cheek or a drop of blood, but the scientific and legal developments over the course of the 20th century reveal how the definition of paternity has changed within a greater social context. “The history of paternity can be told not just as the birth of a solution to a problem, but also as the birth of a problem in itself,” said Nara Milanich, associate professor of history at Barnard, during a recent Lunchtime Lecture, “A Global History of the Paternity Test,” sponsored by the Barnard Center for Research on Women. “No doubt, paternity uncertainty is a recurring trope in Western thought, law, and culture. That doesn’t mean there weren’t also clear, authoritative, and enduring social and legal strategies and methods—protocols if you will—for defining and fixing paternity in the past.”

Ancient Roman law declared pater semper incertus est, “the father is always uncertain,” but as monogamous marriage became the status quo, laws changed to reflect that “the father is he who marriage indicates.”

In the late 19th century, scientists began to examine various means of determining kinship—looking at physical resemblances and biometric systems 
of identification such as fingerprinting and typing blood groups. Paternity 
research often ran parallel to or intersected with eugenic science, which is 
concerned with heredity based on race. Scientists, jurists, and the press closely followed all developments. 

And, as Milanich continues to compile research on scientific and legal history as they relate to paternity, new questions will emerge. How do the scientific developments impact laws? How does genetic fatherhood relate to social definitions of paternity? How are gender roles and identity transformed by the ability to determine paternity definitively by DNA? 

“One obvious question my research needs to address is whose interests are served 
by this new technology and the particular constructions of paternity that it allows?” she said. For example, “We can tie the scientific notions of paternity to the expansion of child rights in Europe, Latin America, and elsewhere in the first half of the 20th century.

“The history of the paternity test obviously has implications for the history of gender, of sexuality, and of family,” she continued. “The history of paternity testing is also inextricably tied to ideas about and practices surrounding race.”

A third hypothesis concerns the biologicalization or medicalization of kinship, which is a process that’s alluded to in some recent anthropological scholarship. She asked, “To what extent are older social and legal definitions of paternity eclipsed by new scientific ones? My preliminary impression is less of wholesale replacement… than of an uneasy coexistence of competing definitions of paternity for most of the century and arguably today. 

“In the 20th century, if science and culture presented paternity as a black box and then proceeded to pry it open, that box proved most definitely to be a Pandora’s box. Any narrative that we can construct about the triumph of scientific truth and justice has to contend with the exploration of legal, social, and ethical ambiguities to which truth has given rise,” concluded Milanich.