Which Half is Mommy?: Tetragametic Chimerism and Trans-Subjectivity

Imagine being told by a doctor that a twin, one you never knew you had, exists inside you. It is well known that fraternal twins arise from two fertilized eggs that develop into nonidentical siblings. Less well known is that these two zygotes sometimes overlap and fuse so completely as to develop into one body with two distinct sets of DNA, a phenomenon called tetragametic chimerism (Tippett 1983). We explore how this rare occurrence exposes complex links between understandings of DNA, human subjectivity, and definitions of motherhood. We focus on cases in the United States of two chimeric women, Lydia and Karen, who were subjected to genetic tests for parentage and subsequently deemed by medical authorities not to be the mothers of their children. The stories of these two women offer opportunities to investigate how definitions of motherhood are constructed, legitimized, and contested by and through science.

According to Marilyn Strathern (1992), nature does not offer us an adequate basis on which to develop a culturally relevant model for kinship. Nevertheless, Western perceptions of kinship increasingly refer to genetic categorizations of bodies as means for defining legitimate mothers and fathers. Aryn Martin (2007a) suggests that there is something of the self that has “become bound up in cells, in response to a cultural rhetoric of genetic reductionism…facilitated by a broader political shift toward privatization and individual responsibility in the late twentieth century in America and in other advanced liberal states” (222). We outline the foundations that enabled this shift toward valuing genetic makeup as a component of modern citizenship. Specifically, we argue that the process of genetic testing works to publicly legitimate the effectiveness of the test itself while acting to stabilize a narrow and powerful definition of motherhood based on testable biological attributes. We then compare the performative aspects of the chimeric mother with notions of “passing” and offer a consideration of human chimerism as posthuman drag. Finally, we argue that the political implications of the established means used to define legitimate mothers extend beyond the trans-genomic quality of chimeric mothers to inform inquiry into reductionist arguments confronted by transgender parents and their children.

For our analysis, we largely focus on the experiences of Lydia and Karen as they are presented in the New England Journal of Medicine, a National Public Radio interview, and a Discovery program with the title I Am My Own Twin. We conduct a genealogy of the conditions that have led to the momentary unintelligibility of chimeric mothers within a genetic reductionist framework and extend this to other trans phenomena. Throughout the analysis, we apply Foucault’s concept of biopower, whereby the chimeric individual undergoes a process of objectification and subjectification within a framework of technoscientific expertise and intervention.

Introducing the Mystery

The Discovery (2005) documentary first introduces Lydia, a Caucasian single mother with two young children and pregnant with a third, applying to receive welfare aid for her family. Through standard procedure, she and the African American father of her children took requisite blood tests to verify parentage. The lab results reported that the father was a match, but that Lydia could not possibly be the mother of her children. She and her family were subjected to multiple tests, emotional anguish, and accusations that she had obtained her children through illicit means. Even Lydia’s father suspected she was not being honest about her conception and pregnancy. Eventually she was accused of welfare fraud and taken to court so that the state could determine parentage and reassign custody of the children accordingly. A tearful Lydia describes dropping her children off to day care with the concern it might be the last day she would see them. Unable to procure a lawyer because of the strength of the DNA evidence against her, she appeared in court alone. Seeing that Lydia was pregnant with her third child, the judge appointed a witness to observe Lydia’s birth and run DNA tests on both her and the infant. The results came back negative, suggesting she was telling the truth, though to Lydia’s chagrin the...