Cautious investors have long known that healthcare spending rises steadily regardless of the direction of the overall economy. It's considered a defensive sector, but it still contains stocks that can shoot through the roof, given the right conditions.This year, the stars aligned for GeneDx Holdings (WGS -7.19%), a genetic testing specialist. The stock rose a whopping 6,070% during the 12-month period ended Nov. 13. To put this gain in perspective, Nvidia's legendary run over the past five years delivered a ...