Fibroblast growth factor receptors (FGFRs) have been implicated in many developmental and regenerative events, including axial organisation, mesodermal patterning, keratinocyte organisation and brain development. The consensus view that this reflects a role for one or other of the nine known members of the fibroblast growth factor family in these processes has recently been challenged by the suggestion that FGFRs might be directly activated by a much wider range of ligands, including heparan sulphate proteoglycans and neural cell adhesion molecules. In addition, (...) two novel soluble ligands for FGFRs have been identified using yeast two‐hybrid technology. Overall, the new findings suggest that in terms of ligand binding the FGFRs might be an even more promiscuous family of receptor tyrosine kinases than was already appreciated. (shrink)

Linda Krieger's paper in this volume relies on the concepts of "equal" and "special" rights, and I focus my attention upon the bivalent view of equality which justifies the creation of special rights. Krieger argues, I point out, that equality of effect is a fundamentally more just consideration than equality of treatment, and special rights allow disadvantaged groups to achieve this equality of effect.