Social science knowledge has been deeply entwined with Australia's family law system in children's cases since the enactment of the Family Law Act 1975 (Cth) (FLA), however, scant attention has been paid to the particulars of these intersections or their consequences. This thesis, a PhD by publication, investigates, describes and critically reflects on this nexus of law and the social sciences. It shows how the foundational 'no fault' philosophy of the FLA aligned with the emerging social sciences of the 1970s, blunting acknowledgement of abuse in the family. It also demonstrates how reforms to the FLA in 1996 and 2006 manifested competing social science research - supporting a 'pro-contact' culture after parental separation, while seeking to protect against the damaging effects of domestic and family violence on the victims and their children. The thesis establishes that the intersections of the social sciences and family law are discoverable in every domain of the family law system. These intersections occur in policy, legislation, the courts, the practices of legal and social science professionals, and the information that is publicly available to the clients. The intersections are profoundly influential in relation to the operation of the family law system and the outcomes experienced by its clients. My thesis analyses the implications of these intersections and the importance of understanding their benefits and some concerns they raise. The thesis demonstrates how social science concepts have contributed to the structure and language of the FLA and the culture of family law practice. It also shows that from the first days of the Family Court of Australia, the social scientists who work in the system have been absorbing the law and legal culture. Further, social science has penetrated the courts, with literature from this discipline being referenced by judges since 1976. Sometimes the research cited reflects matters on the reform agenda at the time. A significant rise in the use of social science in the courts occurred in 2006 when the 'pro-contact' culture was at its highest with the enactment of a presumption that shared parental responsibility was in the best interests of children and post-separation shared parenting time encouraged. I contend that judges were endeavouring to fill gaps in the law when the new legislation did not cover the circumstances of the families before them. However, focus groups conducted with legal and social science practitioners, which are reported in this thesis, revealed that they were not sanguine about judicial use of social science. The participants raised concerns including the lack of judicial expertise in assessing the quality of such research, its contested nature, and the risk of applying general theories to individual families. Meanwhile, social science research was part of the practice toolkit of these practitioners, used to reality test clients' positions and expectations - which were sometimes derived from social science information accessed directly by the clients themselves. The thesis examines 'parental alienation' (PA) as an example of a contested concept from the social sciences that has infiltrated family law to the disadvantage of mothers and children who have experienced family violence or abuse. It has been harnessed by fathers' rights groups in policy advocacy and deployed by individual fathers in family law litigation. I argue that PA can be misused by fathers as a response to allegations of abuse. This shifts the focus of a case from the alleged abuse to whether or not the mother has supported the postseparation relationship of the child with the father. Where PA claims are accepted by the court, orders may be made to change the child's (or children's) living arrangements away from their preferred parent to the other parent. This thesis also analyses interviews with family report writers who conduct social science assessments of the families. The analysis exposes how the law permeates the work of these professionals, and I argue that the assessments influence their practice frameworks, narratives and recommendations. In particular, their perceptions of the role of the presumption that equal shared parental responsibility was in the best interests of children diminished their confidence to make recommendations that did not promote shared parenting. In 2023, the Australian parliament enacted quite radical changes to the provisions of the FLA dealing with children's cases. The thesis concludes with an examination of those reforms, drawing from the research undertaken for this PhD. The reforms commenced operation on 6 May 2024, so review and evaluation lie ahead. This thesis presents a unique way to analyse the reforms and consider their impact. I hope that it will provide participants within the family law system with new understandings and enhance their work in this complex space of human relationships and the law.