The impending reform of the Human Fertilisation and Embryology legislation and the Government's recent White Paper on joint registration of births outside marriage both raise questions about the essential purposes of birth registration. These two developments invite reconsideration of whether an aim of registration is to record the biological parentage of the child or rather to record as parents those who have voluntarily and formally assumed the responsibility of a parent. This question is examined in the separate contexts of births to married and unmarried mothers, adopted and donor-conceived children. This is followed by an analysis of the various rights, interests and obligations which may be thought to be at stake in the birth registration process. The conclusion reached is that the fundamental aim of birth registration is to uphold the right of the child to an accurate record of the event of birth and to identification of the two birth parents. In the small minority of cases in which this is not possible, it is argued that the registration process should make it transparent that legal parentage, as recorded in the register of births and birth certificates, may not be congruent with biological parentage. Reforms are suggested which would shift the emphasis from the mother's autonomy at registration and instead give primacy to the rights of the child.