Entrepreneurs do more than just buy low and sell high; they sometimes also change our institutions, including our categories of thought. New institutional economics has been examining incentives that drive individuals to bring about market-supporting institutional arrangements. There is, however, an aspect of entrepreneurship conducive to institutional changes that has been neglected by contemporary institutionalist theories and that remains underdeveloped in entrepreneurship research. When and how does entrepreneurship bring about institutional change? I suggest that entrepreneurs are agents of institutional change when cultural categorization is ambiguous with regard to what the proper and permissible applications of novel artifacts are. Motherhood, for example, used to be a simple category, but surrogacy changed that radically. Examining newspaper evidence, social surveys, statutory law, and judicial cases, I show how entrepreneurs, by provoking a change in interpretation and judgment, challenged the existing institutional legal ordering of procreation turning a technically feasible method of surrogacy into current practice.