In 1997, the predicament of Gattaca?s Vincent Freeman seemed like nothing more than a far-fetched?though intriguing?vision of the future. Vincent dreams of being an astronaut. He’s intelligent, healthy, talented, committed?a perfect candidate, except for one small matter: his genetic makeup isn’t quite ?perfect? enough.

Fast forward to 2008 and the Genetic Information Nondiscrimination Act that Congress is preparing to sign into law. Suddenly, the futuristic world of Gattaca seems chillingly real.

The Act has become necessary because employers and insurance companies have been using the increasingly affordable access to genetic testing to hire, fire, promote, set insurance premiums, or even deny coverage at all. For these purposes and others, your double helix is quickly becoming the new standard in deciding who is desirable and who isn’t.

Here’s an example: you apply for a job and the company insists you undergo a physical (according to a 2001 American Management Association study, nearly two-thirds of major U.S. companies do so). A DNA sample is taken and it reveals that You’re at a slightly elevated genetic risk of developing breast cancer. You may never get the disease, but your profile shows You’re more susceptible.

You’re in good health, you’ve got the skills and education to do the job, but the company sees your DNA as a risk. What if you do get the disease? How will that affect corporate health care premiums? How much will it cost to hire and train a replacement while You’re on sick leave? Your potential genetic liability means someone else gets the job. They may not be as well qualified, but their genes are.

If you think it couldn’t (and doesn’t) happen, think again. DNA discrimination isn’t new. As The New York Times reports, the Lawrence Berkeley National Laboratory in California carried out secret genetic tests on workers as early as the 1960s (the lab lied, telling workers it was ?routine cholesterol screening?). During the 70s, several insurance companies were found to have refused coverage for blacks ?who carried the gene for sickle cell anemia.? And in 2002, the Burlington Northern and Santa Fe Railway Co. paid over $2 million to 36 employees, settling a lawsuit in which ?the workers claimed the company sought to genetically test them without their knowledge after they had submitted work-related injury claims.?

Although some liken genetic testing to standard health questionnaires that have been around for decades, there’s a major difference: DNA testing means your entire genetic profile can be tested each time a new disease marker is found. Your employer or insurer can continue to screen you for years to come. And It’s not hard to imagine that, once on file, your genetic profile could be put to uses we haven’t even imagined yet (will exclusive schools begin testing for athletic or academic genes?)

As the human genome is mapped, the issue of DNA discrimination isn’t going away. The genetic variants that contribute to diseases such as heart disease and diabetes are being rapidly discovered, and DNA testing continues to rise. Many companies already test for susceptibility to workplace hazards, or for the genetic probability of colon and breast cancer, and consumers can now pay to have their own DNA tested.

Is the Genetic Information Nondiscrimination Act a good idea? Of course. But if human history is any indication, no amount of legislation will control this genetic Pandora’s Box.