In Austen Heinz’s vision of the future, customers tinker with the genetic codes of plants and animals and even design new creatures on a computer. In a makeshift laboratory in San Francisco, his synthetic biology company uses lasers to create custom DNA for major pharmaceutical companies. With the latest technology and generous funding, a growing number of startups are taking science and medicine to the edge of science fiction. In the works or on the market are color-changing flowers, cow-free milk, animal-free meat, tests that detect diseases from one drop of blood and pills that tell doctors whether you have taken your medicine. [...] few founders are pushing the technical and ethical boundaries of science as far as Heinz, who told the Wall Street Journal, “I can’t believe that after 10 or 20 years people will not design their children digitally.” Venture capitalist Timothy Draper, another investor, praises Heinz as an “exceptional leader with a unique passion for his business.” Marcy Darnovsky, executive director of the Center for Genetics and Society, a bioethics watchdog group in Berkeley, sums up Heinz’s belief that “every problem can be solved by engineering” as as a kind of “techno-libertarianism.” “We have to take seriously people like Austen Heinz who say they want to modify future generations of human beings and upgrade the human species,” she said. Scientists modify the DNA of living organisms for many reasons: to make plants resistant to herbicides and pests, for example, or to make research animals mimic human conditions and diseases. DNA is made up of four chemicals represented by the letters A, C, T and G. When Cambrian receives an order for specific genes, it adds DNA chemicals millions of times onto tiny beads that are then layered onto a glass slide. The next step is the key one: A laser programmed to analyze the color combinations ignores the erroneous strands and “prints” the correct ones by pushing them apart from the rest. The final product arrives on a small plastic plate as a powder that customers put inside the cells of an organism. In that case, he said, Cambrian might first ship the plates to an independent facility where experts would put the DNA inside cells, film and analyze it, and make sure that it is safe before releasing it. Because Cambrian wants to keep government interference to an absolute minimum, its CEO insists that behaving well is in the company’s best interest. The Food and Drug Administration oversees gene therapies for humans, and another agency has indicated it will not approve proposals to change parents’ sperm and eggs with the goal of passing genetic changes to their offspring. [...] Darnovsky, the bioethicist, said that it’s less clear what rules would apply to Heinz, who isn’t proposing to design modified humans himself, but to someday provide the DNA to a third-party designer. “A decent percentage of people have really nasty mutations that cause really bad, horrible things,” like Down syndrome and cystic fibrosis, he said. In 2008, he moved to South Korea for a doctoral program in electrical engineering and computer science, where he built the DNA laser printer used today. Next year, the company wants to open a pilot version of the service to academics at a steep discount: $50 for 20 distinct 500-letter strands of DNA.