Drugstore giant Walgreen Co. will hold off selling over-the-counter genetic tests. The company announced Tuesday that the kits would be on shelves this month, but reversed the decision after a stiff response from regulators. "These kits have not been proven safe, effective, or accurate," an FDA rep said. The tests would have been the first low-cost, mass-marketed product to screen for genes associated with diseases like prostate cancer, cystic fibrosis, and diabetes. Click here to read more about the tests. (More genetics stories.)