The current Parliamentary Inquiry into a 'rebuttable presumption' of 50:50 residency taps an aspiration by many children and adults for more meaningful child parent engagement following separation and divorce. But rather than endorse pre-emptive assumptions about family structure, the inquiry should begin with the child's interests and work outwards, argues the author of this article. Discussion includes presumptive and non-presumptive decision-making processes; key patterns of post-separation parenting; the continuing legacy of the motherhood principle; options for parenting plans for school age children; key systemic problems in maintaining a true non-presumptive stance; and what constitutes good practice from a child's perspective. The author states that the proposed 50:50 residence presumption is largely adult oriented, inappropriately focused on structure and, for most separating families, unrealistic. If the proposal was meant to be largely aspirational, and if it succeeds in focusing attention on the fact that too many children miss out on receiving what both parents or other significant carers can offer them after separation, then the inquiry will have been a worthwhile development, the author concludes.