Few parents-to-be consider that their child may be born with ambiguous sex. Still, parents of a newborn child with ambiguous sex are expected to make a far-reaching decision for the child should the child be operated upon so that it has either female or male genitals? The aim of this article is to examine, phenomenologically, why parents decide to have their children undergo genital surgery when it is not necessary for the childs physiological functions. Drawing on phenomenological work by Maurice Merleau-Ponty, Simone de Beauvoir and Sara Ahmed, we examine parents frustration when their childs sex is ambiguous and their experiences of the practice of medical sex assignment. We also examine parental identity work when the child has been assigned a sex and the interaction between parents and medical professionals when parents make decisions regarding surgery on their child. Furthermore, we provide a critical perspective on the surgical practice.