Abstract
Specific developmental dyslexia, a condition characterized by reduced reading, spelling, and writing abilities combined with normal intellectual capacity, has challenged geneticists and ‘environmentalists’. Although most of the strikingly controversial results can be traced to differences concerning diagnostic decision-making, there are many hints of a genetic contribution. Twin studies and extensive pedigree analysis substantiate this view, but it is too early to infer a definite mode of inheritance from the available data.