RT Journal Article SR Electronic T1 Let's keep metaphysics out of medical ethics: a critique of Poplawski and Gillett. JF Journal of Medical Ethics JO J Med Ethics FD BMJ Publishing Group Ltd and Institute of Medical Ethics SP 206 OP 209 DO 10.1136/jme.18.4.206 VO 18 IS 4 A1 F J Leavitt YR 1992 UL http://jme.bmj.com/content/18/4/206.abstract AB I argue that the concept of 'longitudinal form', which Poplawski and Gillett have introduced into ethical discussions about embryos and gametes, involves too many metaphysical subtleties to be a useful aid to making moral decisions. I conclude by suggesting a criterion for relevance in medical ethics.