We are born, we die. For the duration of our lives, we share this assumption about our common mortality. We plan our affairs and measure our success against a traditional lifespan - career, marriage, children, retirement. Our universal frailty binds us, rich and poor, to the knowledge that at some point we all get sick and perish. We just don't know how. Or when.

But in a series of off-the-record discussions with top scientists, participants at the Annual Meeting heard about how science is progressing so fast that it is challenging our assumptions about the human experience. Death remains inevitable, but the when is being pushed out by advances in medicine. The how, too, may now be less a mystery than a probability. By unravelling the very essence of our individuality, DNA, we may be able to forestall the inevitable, cheat death and alter what we once simply accepted as grim fate.

In practical terms, these developments are sure to have a profound impact, altering the rules of the labour force, the calculus of healthcare, our concepts of age, of equality and of privacy. They will eventually force us to consider what the human body is and what constitutes a full life. If nothing else, science is outpacing the public's ability to understand its accomplishments and weigh the implications.

The finality of paralysis, for example, is being challenged by developments in neurotechnology that link the brain directly to machines. Once, a severed spinal cord was irreparable. But by implanting electrodes in the brain, doctors have been able to allow at least one paraplegic to operate a robotic arm and surf the Internet with only his thoughts. Cochlear implants can now restore hearing in many people. Deep brain stimulators are being used to treat epilepsy and Parkinson's disease. Retinal prostheses have been used successfully to restore sight.

Such developments hold out the possibility that robotic limbs could be controlled by the wearer's brain to restore natural motion. Advances in bioengineering are already creating prostheses that allow almost natural movement, and even let their wearers regain the ability to feel pressure and weight. Soon, artificial legs will not only allow patients to walk on the beach, but to feel the sand beneath their feet. New biomaterials could allow doctors to regrow nerves entirely.

These developments hold out hope to accident victims, paraplegics and amputees, as well as to victims of diabetes and strokes. Some wonder, however, how long it will be before synthetic body parts become part of the cosmetic surgeon's arsenal, allowing us to enhance not only our appearance but also our performance.

Advances in genetics, meanwhile, are providing new weapons in the fight against cancer. Biomarkers can now be used to identify individuals at risk and treat them. By exploring the genome, scientists expect to uncover the primary reasons for virtually all common diseases within the next five years. Using their understanding of the genome, scientists are compiling a cancer genome atlas that identifies which genes control susceptibility to certain cancers. Researchers have already identified genes that control the risk of adult-onset diabetes, asthma, breast cancer, hypertension, macular degeneration, prostate cancer and heart disease.

Greater understanding of genetics promises to revolutionize medicine, allowing doctors to develop therapies that pinpoint afflicted areas - even individual cells in the body. Genetics already make it possible for physicians to compile treatments tailored to each patient - "genomic medicine". An account of the medically significant genes in a person's DNA is now available for about US$ 1,000.

Insurers and regulators expect that such individualized treatments will save them money, even though they are likely to cost individual patients much more. Genomic medicine also poses a challenge to the conventional model for drug discovery and development: clinical trials for a market of one are impossible and lack the scale companies need to justify investing in developing such treatments. Scientists say this is likely to force profound changes to the pharmaceutical industry, perhaps favouring smaller companies that can serve in a role akin to Hollywood producers, assembling different scientific actors and specialists to crack a specific medical problem.

The concept of personalized diagnosis and treatment also challenges the traditional assumption that each person needs, and is entitled to, certain common medical procedures. They also pose a problem for conventional healthcare systems, which rest on democratic principles of equality - the expectation that all citizens should be treated the same. The value of genetic analysis lies in the fact that one patient should not be treated like another.

Patients and doctors fear that people with a genetic predisposition to disease will face discrimination, that employers or insurers might reject them. Genetic revelations also present another ethical dilemma: whether the knowledge of a likely illness will improve one's quality of life. Does informing a patient they are likely to develop an incurable and fatal disease within the next decade help them? How will it affect their role in society?

Science may ensure our lives are longer, but will they necessarily be fruitful? By decreasing our mortality, the total cost of healthcare will rise. As we are better able to prevent and bounce back from acute injury and disease, health systems will need to shift attention to the rising cost of chronic diseases such as diabetes, obesity and other lifestyle-related diseases like lung cancer. Governments are already stepping in to limit factors contributing to chronic disease: banning smoking, for example, or unhealthy foods. New York City monitors diabetics' blood-sugar levels to reduce treatment costs, while Japan plans to require yearly medical checkups for citizens over 50. The burden of chronic disease is so large, many say, that it could alter cultural traditions about which behaviours are private and which are the concern of society at large. Medicine may become more personalized, but your health will become a matter of public interest.