In principle, DNA analysis has made it possible to establish to a very high degree of probability the human source of even a minute quantity of biological matter - most notably blood, semen or saliva. The science is complex, and the degree of certainty not absolute, especially when it is necessary to differentiate between twins or siblings. But it has begun to revolutionise the process not only of detection by police but of proof in court. What is particularly welcome is that it is as potent in eliminating those who are wrongly suspected or accused as it is in tracking down the guilty.

LRB 20 January 2005 | PDF Download