Time-sensitive hybrid model for parent allocation in IVF embryo mix-ups

In in vitro fertilisation (IVF) mix-ups and contested parenthood, Prince and colleagues argue that the familiar 'genetic presumption' in parenthood disputes should be treated as rebuttable in favour of the gestational relationship, and that custody and guardianship outcomes will typically be resolved under best-interests standards, with biological relatedness operating as one relevant factor among others. Their paper effectively re-centres moral attention on pregnancy, embodiment and gestation in a domain often organised around DNA and prior intention. This response agrees that gestation generates morally weighty interests and that a purely genetic default can obscure how parental bonds are formed and sustained.However, IVF mix-ups are a structurally distinctive category: they arise within an ex ante consent-based system of embryo creation, allocation and implantation, where predictability and institutional accountability are central. To preserve these values without collapsing into rigid geneticism, I propose a time-sensitive hybrid model. On this approach, genetic-intentional parenthood supplies the default entitlement at the point of error identification, reflecting the consent architecture of assisted reproduction, while settled attachment and caregiving reliance modify the remedy when discovery occurs late. The model thereby protects relational stability while preserving identity interests and institutional accountability, offering a temporally staged allocation framework that better fits assisted reproduction's underlying structure.