Investing in biotechnology (biotech) stocks is often thought of as being too risky for most investors. That’s not necessarily the case. While many investments are viewed as speculative, several blue-chip companies stand out among the top biotech stocks to buy for a conservative retirement portfolio. If and how you get involved depends in large part on your risk tolerance. For example, many small-cap biotech companies who trade as penny stocks. These can offer the chance turn a small investment into millions ...