"Applied DNA Sciences, based in Stony Brook, N.Y., has a new technology that embeds botanical DNA into fibers that can then be sewn into a garment. The DNA is detectable under a specific light and can be assigned to a specific brand. It can’t be copied. The company’s clients include two European luxury brands, which it declined to name."

Fashion Fakes Get More Sophisticated - WSJ.com

Isn’t the point of DNA that it is easily copied?  PCR anyone?