LETTER : Criminals are made, not bred

Sir: The question of the genetic determination of criminal behaviour has some facets not mentioned in your leader "No natural born killers" (13 February). What is considered criminal varies from culture to culture and, within a given gene pool, varies with time.

So, in western Europe killing has not always been a criminal act, while the lending of money for interest occasionally has; homosexual activity and marrying one's deceased wife's sister were criminal acts, but are no longer illegal. These variations show the extraordinary sensitivity of genetic material to cultural and legal changes in society and raise all kinds of fascinating questions.

For example, suppose that one were living in 19th-century Britain and were genetically pre-disposed to the criminal act of marrying one's wife's sibling when the spouse passed away (women are, no doubt, merely carriers of this gene). When this offence is removed from the statute book, what happens? Is it more or less likely that the marriage would take place? The whole question hinges on precisely what is genetically determined; is it the fatal attraction to one's wife's sister (and which sister, if there are many?) or is it the inevitability of the genetically determined path to crime, now thwarted by parliament?

The identification and isolation of the gene responsible for large-scale pension and insurance fraud is another rich seam for experimental work. No doubt we can look forward to reports of both empirical and theoretical investigations of these matters in the scientific literature, and a humane commentary by yourself.

Yours faithfully,

D. B. Cook

Department of Chemistry

University of Sheffield

Sheffield