Anyone for tennis, at the age of 150?

Scientific progress promises us far longer, happier lives. Yet the 'bioconservatives' want to stop it

By the end of this century, the typical European may attend a family reunion in which five generations are playing together. Great-great-great grandma, at 150 years old, will be as vital, with muscle tone as firm and supple, skin as elastic and glowing, as her 30-year-old great-great-granddaughter with whom she's playing tennis.

After the game, while enjoying a plate of vegetables filled with not only a solid day's worth of nutrients but medicines she needs to repair damage to her ageing cells, she'll be able to chat about some academic discipline she studied in the 1980s with as much acuity and memory as her 50-year-old great-grandson, who is studying it now.

The younger members of her extended family will have never caught a cold. From birth they will have been immune to most of the shocks to which human flesh has long been heir, such as diabetes and Parkinson's disease. Her grandson, who recently suffered a car accident, will be sporting new versions of the arm and lung that got damaged in the wreck. He'll be playing a game of football as skilled and energetic as anyone else there.

Aids and Sars will be horrific historical curiosities for the family to chat about over their plates of superfat farm-raised salmon. Surrounding them will be a world that's greener and cleaner, more abundant in natural vegetation, with less of an obvious human footprint, than the one we live in today. It will be a remarkably peaceful and pleasant world even beyond their health and wealth—antisocial tendencies and crippling depression will all be managed by individual choice through biotech pharmaceuticals and even genetic treatments.

This idyll is more than realistic, given reasonably expected breakthroughs and extensions of our knowledge of human, plant and animal biology, as well as mastery of the manipulation of these biologies to meet our needs and desires.

Although you would think most people would devoutly wish for this vision, an extraordinary coalition of left-wing and right-wing bioconservatives is resisting the biotechnological progress that could make it real. Forget Osama bin Laden and the so-called clash of civilizations. The defining political conflict of the 21st century will literally be the battle over life and death.

On one side stand the partisans of mortality. From the Left, the bioethicist Daniel Callahan declares: "There is no known social good coming from the conquest of death." On the Right, stands Leon Kass, former head of George Bush's Council on Bioethics, who insists: "The finitude of human life is a blessing for every human individual, whether he knows it or not."

Such people counsel humanity quietly to accept our morbid fate and go gently into that good night, as we and our ancestors always have. For example, both Kass and Callahan persuaded President Bush to impose strict limits on human embryonic stem-cell research. Kass strongly favoured the proposed UN treaty that would have imposed a global ban on therapeutic cloning to produce stem cells. The treaty, which was almost approved by the General Assembly in 2004, would have outlawed therapeutic cloning research being done in the UK, which Kass denounced as having transgressed a "moral boundary".

Opposing this influential alliance of bioconservatives stands the party of life, whose champions include Aubrey de Grey, a theoretical biogerontologist at Cambridge University, who rage against the dying of the light and yearn to extend the enjoyment of healthy life to as many people as possible for as long as possible.

This conflict is brewing because the rapid progress in biotechnology will utterly transform human life by the end of this century. By the middle of this century humanity may see 20 to 40-year leaps in average life spans; human bodies and minds enhanced by advanced drugs and other biotherapies; the conquest of most infectious and degenerative diseases; and genetic science that allows parent to ensure that their children will have stronger immune systems, more athletic bodies and cleverer brains. Even the possibility of human immortality beckons.

Researchers are making progress on figuring out why our bodies age and are discovering pathways to prevent it. Companies such as Elixir, based in Boston, are hot on the trail of compounds called sirtuins that retard ageing in simple organisms and which they believe will work for people, too. Other researchers are pursuing techniques to renew and replace the tiny cellular powerplants called mitochondria that most gerontologists think are the cause of the damage that leads to ageing.

Stem-cell researchers are getting ever closer to working out how to create perfect transplants to replace and restore damaged tissues and organs. The Geron Corporation, for example, plans later this year to begin experiments using human embryonic stem cells to repair broken spinal cords. Amazingly fast progress is being made using RNA interference, which is a technology that can selectively turn genes on and off in our bodies.

Researchers recently reported that they can turn off the genes for producing "bad" cholesterol in monkeys. If this works for humans, and there seem to be plenty of reasons to believe it will, it could slash heart disease rates.

Since 1978, more than one million babies have been born using assisted reproduction techniques. More than 5,000 healthy children have been born using pre-implantation genetic diagnosis in which embryos were tested for specific disease genes before they were implanted in their mother's wombs. By the middle of this century, technologies such as artificial human chromosomes will enable parents to endow their children with genes for good health, strong bodies and sharp minds. Instead of submitting to the tyranny of nature's lottery, which cruelly blights futures with sickness, stunted mental abilities and early death, parents will be able to open more possibilities for their children to lead flourishing lives.

Beyond human biology the possibilities are immense too. Plants and animals genetically enhanced to resist drought, insects and disease and to provide higher yields and improved nutrition will enable humanity to produce more food, fibre and fuel on less than half the land currently used for agriculture, allowing huge swaths of Earth to revert to nature.

The highest expression of human nature and dignity is to strive to overcome the limitations imposed on us by our genes, our evolution and our environment. Future generations will look back at the beginning of the 21st century with astonishment that some well-meaning and intelligent people actually wanted to stop biomedical research just to protect their cramped and limited vision of human nature. Our descendants will look back, I predict, and thank us for making their world of longer, healthier lives possible.

This story originally appeared in the Times of London.