Above the borderland between normal and neoplastic development.

This dialogue between the Editor-in-Chief of the Int. J. Dev. Biol. and a leading figure in human pathology and mammalian embryology highlights the close links between the biological interpretation of neoplasia and differentiation processes which normally occur during development, particularly in the case of teratomas. In addition, it emphasizes how a capacity for work, a firm will to progress, and enthusiasm for science and medical practice can overcome the not insignificant obstacles with which one meets during a life of scientific, academic and clinical dedication.