We are all programmed to age and die, but it doesn't have to be that way. If cells were not programmed to age, if the telomeres, which govern the number of times a cell may divide, didn't shorten with each division, if our bodies could repair damage due to disease and ageing "from within", we would certainly live longer and healthier lives and might even become immortal.
Scientists from all over the world are reporting research which could, in principle, lead to the indefinite extension of life, reprogramming cells so that they did not age, making telomeres that would constantly renew themselves, and repairing cell and tissue damage as it occurred. Next month in this country the Chief Medical Officer's Expert Group is due to report to ministers on advances into human embryonic stem cells, which constitute the most promising avenue of research into increased longevity.
Suddenly the prospect that humankind could become immortals is more than a science fiction fantasy.
There is, of course, a sense in which we already have the secret of eternal life. Our genes are "immortal" in that they come from our earliest humanoid ancestors, and their genes came from the earliest forms of life on earth. The genes we pass on to the next generation, by whatever method of reproduction, may survive indefinitely into the future. But, of course, the quest is for personal immortality. Yet if that can be achieved, though many individuals will be delighted humanity will be in deep trouble.
There is a key difference between trying to make existing people immortal and engineering immortality into future generations. To make you and me immortal scientists would have to make each type of our cells capable of regeneration. This would be a comprehensive task, which might be achieved by putting into the bloodstream many differently programmed stem cells. They would have targeting molecules attached that would cause them to colonise the different bodily systems which might be affected by disease. Since no technology is 100 per cent effective, repeated interventions would be necessary, but it might be possible in this way to extend existing lives indefinitely.
But in the long term it may be possible to "switch off" the ageing process and maintain a repair programme in cells, by modifying the cells of the early embryo or even the gametes prior to conception. If all the early stem cells in an embryo had their ageing programme switched off, and were programmed to regenerate, then this immortality would be passed on as the cells multiplied and differentiated, eventually affecting every cell in the body as it was formed. The resulting children would be truly immortal.
But immortality is not the same as invulnerability and even these immortals could die or be killed. We do not know when, or even if, such technologies could be developed and made safe enough to use. But if it did happen it would have serious implications.
One thing we do know is that the technology required to produce such results would be expensive. For existing people with multiple interventions probably required, the costs would be substantial. To modify every new embryo, people would have to be determinedly circumspect about procreation and would probably need to use reproductive technologies to have their immortal children. Even in technologically advanced countries "immortality" or increased life expectancy would be likely to be confined to a minority of the population.
In global terms the divide between high-income and low-income countries would be increased. We would face the prospect of parallel populations, of "mortals" and of "immortals" existing …