Greek family courts routinely favour mothers in child custody proceedings even in cases where residence with the father would clearly be in the best interests of the child. This discrepancy between the law and judicial practice is justified by the courts on alleged bio-social grounds but these have never been identified, let alone elaborated in any way and no theory from the field of neuroscience or developmental psychology has ever been cited as the groundwork for the courts’ approach. This arbitrariness and the concomitant absence of legal certainty stems from the absence of a dedicated family court system. As a result, generalist judges are fearful of expressing themselves in non-legal areas, such as neuroscience, or otherwise have little awareness of developments in these areas. Because judgments never make any scientific pronouncements, litigants cannot challenge the courts on scientific grounds. This gender bias has its roots also in taboo theory. With minor exceptions, experts universally agree that attachment theory is gender-neutral and that children, especially infants, form meaningful primary attachments to the person who provides them with a loving and caring environment. Ultimately, in many cases custody arrangements lead to financial bartering in exchange for additional visitation time by the father or exclusion of the father from the child’s life. The injurious nature of such an outcome is analysed here from a neuroscience perspective.