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Q1: What precisely are the medical procedures when a dying person is to be an organ donor? I don't think anyone can give "informed consent" until we know this. Anne Hardy, Reading.

A1: If the recipient of a transplanted organ is to have the best chance of long term survival it is to all intents and purposes essential, for a successful thoracic organ transplantation of the heart or lungs, for the surgeons to remove the organs from someone who is brain stem dead but still has a heart beating. It is also highly desirable that those who are having a kidney or liver transplant should have equally potentially viable donated organs. The necessary discussion with relatives before donating an organ can present problems as many potential donors have suffered sudden cardiac arrest or have been involved in an accident.

The Human Tissue Act of 1961 allows organs to be collected from the patient provided the patient has expressed this desire and the next of kin of the patient have no objection. If the patient's death has been one that would make it a coroner's case, that is an accidental or homicidal death, or has occurred at a time when the patient hadn't seen a doctor recently, the coroner's permission is also required. This is a brief summary of the opting in law that operates in the UK. In many European countries, including Austria, Belgium, Spain and France the "opting out" law prevails. In this the person is assumed to have given consent unless they have formally recorded their objection to being a donor. In these countries where a brain dead person is assumed to have given consent it is still the custom, even if it is not required by law, for the question of donorship to be discussed with relatives.

One of the other ethical questions is whether it is ethically acceptable to keep someone alive artificially by ventilation, as for example after an intracranial haemorrhage, until such time that the person is both brain dead and available to the transplant team so as to allow a well-planned organ donation. The problem is that the donor patient him or herself will not benefit from this treatment, and ethics demand that all medical treatment is only carried out if it to be to the benefit of the patient. Whether it is of inestimable benefit to the recipient is of course relevant but not the prime consideration. The Department of Health decided a few years ago that this interventional ventilation to keep the about-to-be-removed organs in the best condition was not ethically acceptable. So far as I know this ruling still holds.

Living donor transplantation is always to be preferred whenever possible, but there are not many and certainly not enough, volunteer living donors, whether the donor is a member of the family or a stranger. The effect of, for example, giving a kidney on the donor's health as well as on the recipient's future prospects has, and needs to be carefully thought out. The assessment must be explained to both donor and recipient. Although there is an obvious risk of going through life with only one kidney this hazard is not as great as is supposed. Long term statistics don't show that people who have had a normal kidney removed have any increased incidence of hypertension, disease in the remaining kidney or any other long term medical consequences. There must be a tiny increase risk of disaster because of accidents, or chance happenings such as a kidney cancer in the remaining kidney, however these risks are so small that they don't affect the statistics of life expectancy that remains unaltered in people who are left with only one kidney after donorship.

As in all transplant operations donor and recipient must be blood and tissue compatible. The donor must be free of serious disease and not be suffering from any disease or condition that could be transmitted to the recipient by the transplanted organ. Some people are rejected on grounds of age, this depends very much on what organ is being transplanted and the donor's state of health. The rules governing age vary from unit to unit and country to country. It goes without saying that a living donor must be a good operative risk and not suffering, for example, from serious asthma, obesity or other chronic condition.

I would suggest that you ask your GP about donorship and he or she could arrange for you to talk to whoever deals with donors in your area. Everything that is possible needs to be done to encourage donorship. This in time will be achieved by fostering good will in the population and a greater understanding of the differences that a transplant can make to the recipient, not only in the terms of life expectancy but also as regards the quality of life.

Q2: When someone fills in the opt out card it could say that the opter out would not then qualify themselves at any time for a donor organ should the need arise. M Kellett, Hampshire.

A2: As much as many people might think that this was a logical and deserved step, I don't think that the usual ethical considerations that determine how doctors act would allow this clause to be inserted. When confronted by any situation doctors have to do their best for a patient regardless of the patient's past life, political opinions, lifestyle, race or religion.

Q3: I am a renal transplant patient who will shortly be on the waiting list for a new kidney. Waiting for a transplant can be hellish, many older patients do not survive the rigours of dialysis. Many people never get one because of the shortage of organs. Even when an organ match is found it is still no guarantee that the body will accept the new organ long term. I think that the new regulations, whether it is the government's right to interfere with these matters or not, will save many lives. I understand that many people have religious grounds on which they reject organ donation, but I would invite them to visit a dialysis unit, or even worse, a unit where patients await liver transplants, to see how they feel about the value of life then. Rivka, 19, Bristol.