My main field is distributive justice, which is a part of political philosophy that examines how social institutions should distribute benefits and burdens within a family or a nation-state, or across countries or generations. This requires assessing general principles (including equality, priority, and sufficiency) as well as policy responses (such as taxation and public spending proposals) to specific problems like gender inequality, local and global poverty or climate change. I have written from a biologically-informed perspective about gender, nonhuman animals, personhood and the distinction between natural and social inequality. I have also written about more specific issues, such as how to distribute the costs of child-rearing, the right to sea-access for landlocked states, the moral limits on religious and cultural accommodation, xenotransplantation and the Non-Identity Problem, and the distinction medical ethicists draw between therapy and enhancement.