Alison Scott introduced a lively debate and discussion on human genetics, and some of the ethical issues which arise in this rapidly developing scientific field. She presented the background information to put the material in context, and pointed out that advances in genetics research are proceeding at a pace far faster than the ethical debate or the legal framework can cope. As a topical example, she referred the emergency legislation the UK Government is planning to push through, to outlaw the experiments in human cloning which the Italian Doctor Antinori wishes to carry out in this country.

These debates are partly sponsored by the Wellcome Foundation and AstraZeneca, both of which have interests in the field of genetic testing and treatment. In addition to background material and references, some questionnaires had been prepared which, it was recommended, the participants should complete in pairs, ideally of people who did not know each other well. To produce manageable results, these questionnaires concentrated on the narrow issue of knowledge and choice. If we are able to diagnose a disease, or a predisposition to it, but have yet to find a cure, is it better not to be tested? What about the privacy of the results, and to whom do you have a duty to inform? And what about the threat of discrimination?

The questionnaires presented a number of such dilemmas for the participants to consider and debate, first in pairs, to tick boxes and add comments; and then in small groups, moderated by the presenters. At this stage, there was an opportunity to change one's answers, or fill in a second questionnaire; and part of the evening's purpose was to provide feedback to the sponsors on the extent to which the participants did indeed modify their initial opinions as a result of group discussion.

Dr Janice Wood-Harper gave a concise history of the science of genetics, from the pea-breeding experiments of the monk Gregor Mendel in 1865; through the Nobel Prize-winning analysis of the structure of DNA by Watson and Crick (and others) in Cambridge in 1953; the deciphering of the way in which the ATGC base triplets code for amino acids, and thereby control the synthesis of proteins, in the 1960s; and gene sequencing in 1977; to its apotheosis in 2001, with the publication of the draft result of the Human Genome Project (HGP), years ahead of schedule owing to unforeseen advances in technology and a remarkable, international cooperative effort.

The Human Genome contains some three billion pieces of information, made up of four chemical bases, represented by the letters A, C, T and G, which connect in pairs to form the rungs of the familiar DNA "double helix" ladder. A always connects with T, and G always connects with C. During cell division and replication, the ladder unzips, and each strand then acquires a complementary strand, to rebuild a new molecule of DNA identical to the previous one. DNA is an enormously large molecule : the human one, so tightly packed into the nucleus of almost every cell of our bodies, would be two metres (over six feet) long if it were stretched out. Nevertheless, the number of genes it carries turns out to be between 30,000 and 40,000, considerably fewer than first expected. Over 95% of its length is "junk" DNA, of which the purpose is so far unclear. For readers who wish to learn more, Manchester University are running Continuing Education courses, and of course the WWWeb has vast resources, links to some of which were provided in the notes. There is a link to a page listing the entire genome of a common bacterium below.

It has been said that the 21st Century will be the Century of Genetics. Despite scares over human cloning and so on, advances in genetics are not all bad : we can hope for genetic "fixes" for some inherited diseases, such as cystic fibrosis. One day, it may even be possible to identify a predisposition to certain behavioural traits. The carrier gene for cystic fibrosis has been found on Chromosome 7, and it is already possible to test for the presence of this gene in the embryo. Unfortunately, although this can be corrected "in vitro" on a laboratory scale, it has not yet been possible to develop a safe and reliable "vector" (usually a modified virus) to carry out the genetic repair in the living body. Alzheimer's Disease is multi-genic, carried across four chromosomes, so this is even more difficult to identify and treat.

There has been a degree of over-optimism that a genetic cure will soon follow the development of a new diagnostic test, and some realism should be encouraged. Even if effective treatments are developed, it seems inevitable that they will remain very expensive. One day, we may indeed be able to look forward to the eradication of inherited diseases, and more worryingly the enhancement of genetic characteristics and so-called "designer babies", super-breeds and clones, but probably only for the rich.

Genetic knowledge can inform our decisions about reproduction, healthcare, employment, insurance and so on. It has therefore become a hot commercial topic : the big biotechnology companies, most of them American, stand to make a lot of money from the sale of testing kits, which perhaps may even become as widely available as home pregnancy tests are today. These developments carry serious implications for privacy and consent, and open up possibilities of social division, perhaps unfairly based on unreliable testing or interpretation. At present, only the test for a predisposition to Huntingdon's Disease, which is very accurate, is permitted to be used as the basis of insurance underwriting, but commercial pressures may erode this limitation.

Sue Roberts raised the question of the cost of testing itself, and of sympathetic counselling, with which many of these tests need to be accompanied. Shortage of such resources is of major concern, and may turn out to be the limiting factor in the applicability of the new tests. All agreed that gaining the benefits of new genetic techniques for some must not be allowed to create a genetically disadvantaged underclass for others, discriminated against in employment and opportunity. This division could extend both culturally and internationally. As has been seen in the case of infectious diseases, the development of tests and treatments tends to favour those communities which can pay for them. Even serious inherited diseases which are rare, or which rarely affect the wealthier countries, may never have genetic treatments developed to diagnose and combat them.