Both companies have helped pioneer important medical breakthroughs.Investing styles tend to evolve as people age. Seniors who are already retired often look for steady, reliable, dividend-paying companies. Younger investors, on the other hand, can afford to take more risks and tend to seek out companies that, despite being more volatile, also boast significant long-term upside potential.With that in mind, let's consider two stocks that people in their 30s -- who are still a good distance away from retiremen ...