Gabby Dover's polemic against the Darwinism Today lecture series, including my book Divided Labours ("Darwinian devolution", THES, February 26), is so thoroughly misleading that readers deserve to be disentangled from his web of confusion.

Divided Labours's thesis is that men's greater average competitiveness and risk-taking is in part a legacy of evolution and that sex differences in these temperamental traits are partially responsible for the "glass ceiling".

Dover has "no quarrel" with the proposition that differences between the sexes may cause men and women, on average, to have different priorities. However, he castigates me for two "mistakes". One is not a mistake at all; the other would have been had I made it.

The first "mistake" is my reliance on mainstream evolutionary theory, a flaw my book shares with most respectable books on evolution.

ÖйúAƬ

My second error is my "incorrect evolutionary genetics". Dover asserts that "an assessment of a genetic contribution to a behavioural trait based on heritability studies in twins" does not prove that differences between men and women are "genetically determined". He denounces me for claiming that average sex differences in temperament exist "just because" genes contribute to individual temperamental differences.

Yet I explicitly cautioned that "the fact that there is a genetic basis for individual differences within a group does not mean that differences between groups necessarily have a genetic basis". (For example, height within a population varies in part for genetic reasons, but an average height difference between populations may be caused solely by different nutrition.) I also explained that the genetic studies show only that personality traits are influenced by genes, a fact uncontested by Dover.

ÖйúAƬ

Finally, my book drew on many disciplines other than genetics, including endocrinology, developmental psychology and anthropology.

Dover's hostility towards accepted principles of biology appears to have led him also to reject accepted principles of book reviewing.

Kingsley Browne Professor of law Wayne State University law school Detroit, Michigan, US