Connect with Fast Company

You wouldn't think that creating old, pumped-up mice would pose much of an ethical dilemma. But University of Pennsylvania professor Lee Sweeney was invited to speak before the President's Council on Bioethics a few years ago because that's exactly what he does. The commission, created by George W. Bush to map out the moral and ethical consequences of advances in medicine and biotechnology, heard Sweeney describe his research into ways of turning back the rodents' biological clock, reversing the deterioration of muscle caused by aging and even degenerative diseases. The treatments, Sweeney explained, had all but halted, and in some cases reversed, the age-related decline in mouse muscle. Essentially, he'd given a 27-month-old mouse (age 80-plus in human years) the body of a 6-month-old.

But Sweeney is not building his buff little Mus musculus with a new drug or physical therapy. He's injecting them with genes, extra copies of the very gene that causes our own bodies to develop muscle mass. And his research points the way not only toward a possible slowing of diseases like Lou Gehrig's but to a way of giving perfectly healthy men and women bigger and stronger muscles--permanently, after just a single dose. As Sweeney puts it, one of these days you could "just take a few injections of the virus [that delivers the genes] and a month later, while you're watching television, your muscles have gotten bigger."

Designer muscles are just one potential feature of the Body 2.0, a new, customizable version of ourselves made possible by the decoding of the human genome and an evolving understanding of, and ability to manipulate, our own genetic makeup. The aftermarket options now in development are already astonishing: While Sweeney's team is working on muscle regeneration, others are looking at ways of genetically, permanently boosting red-blood-cell count (and thus aerobic endurance), creating whole-body tans (to ward off skin cancer), controlling metabolism and hunger hormones (to prevent obesity), spurring hair growth, and mimicking the effects of Viagra (on an on-demand basis). Researchers are saying that it may be possible in the next two decades to increase the body's healing power, induce it to regenerate lost limbs or organs, even to slow or halt human aging.

Obviously, such treatments could change us forever. University of Florida associate professor Sergei Zolotukhin, for example, called obesity gene therapy "the couch potato's dream." But the Body 2.0 isn't here yet. Gene therapy--which simply means altering the genes of a living person--isn't even considered safe; clinical trials have caused the deaths of at least seven people. But the writing is on the wall. More than 800 clinical gene-therapy (GT) trials have been approved so far. GT products are projected to account for $125 million in sales in 2006--primarily to researchers and universities looking for ways to apply them. By 2011, analysts expect GT products to be approved for clinical use, and the market to swell to $6.5 billion.