| Abstract: | In its ascendancy, the study of human genetics is shifting from the inheritance of physical structure to that of behaviour and personality; seeking the secret machinery which joins the inherited code to the quirk of character. At the start of the century human behaviour was thought to be largely learned and to stem from upbringing, the blank slate of personality being moulded by parents and events. What had been learned could be unlearned and this accorded with the idea of free will expressed in Cassius' claim that ‘the fault, dear Brutus, is not in our stars, but in ourselves, that we are underlings’. Now, at the century's close, the influence of breeding is back in fashion, bringing the implacable effects of genetic determinism and bad blood. The implications for the successes and failings of the ‘normal’ population are far-reaching. In learning disability, many of these ideas are contained in the concept of the ‘behavioural phenotype’. |
