This article addresses the child’s right to know their genetic origins in mitochondrial donation. It focuses on the UK’s public debate on mitochondrial replacement techniques and examines the claims-making activities that shaped the donor information regulations. During the public consultation, downplaying the significance of the mitochondria helped distinguish mitochondria donors from gamete donors and determine their relational status with the resulting child. As a result, according to the Mitochondrial Donation regulations, mitochondria donors, unlike gamete donors, will not be required to (...) be identifiable to the resulting child. I argue that, in the UK, similar to donor conception, public understanding of mitochondrial donation is shaped by a “calculus of genes”: simplified accounts of how genes determine the resulting child’s characteristics and identity. While the donor conception regulations ascribe social meaning to the passage of genes, the mitochondria regulations strip the social meaning away from the donation based on the assumption that the genetic contribution made by the donor is quantitatively insignificant in influencing the identity of the resultant offspring. The nature of the genetic material itself should not be considered as a privileged standpoint from which to decide on social meaning of the donation or the rights attached to it. (shrink)