Over the course of The Motley Fool's 26-year history, one of its guiding principles has been to look for the positive side of the story. The best stocks, services, and stories have produced some of the best returns for investors. Those innovators don't always pay off fast, but that's OK -- when you buy and hold for the long term, you can afford to be patient. And speaking of patience -- or rather, of patients -- it's time for Rule Breaker Investing host David Gardner to pick another of his five-stock samplers, and this time, his theme is medical miracles. Each company he's recommending has big potential to cure a condition that has thus far been incurable or to create new possibilities where none existed before.

By definition, that means that his picks this time may carry more risk than some of his prior recommendations. For every biotech breakthrough that makes it to market, there are many promising candidates that don't pan out. Still, three years from now, the Motley Fool co-founder expects that on the whole, this basket of stocks (all of which are all already active recommendations in his portfolio) will be beating the S&P 500 -- and saving lives, too.

Recommendation No. 1: Amgen (NASDAQ:AMGN), one of the oldest and largest biotech companies, and he'll happily explain why he's optimistic about it.

A full transcript follows the video.

This video was recorded on April 3, 2019.

David Gardner: Five stocks. For each of these, I'm going to give you two things that I like about the company and why I'm picking the stock, and then one thing to watch. As usual, we will do these alphabetically by company name.

Let's lead it all off with company No. 1: Amgen. Amgen is one of the oldest biotechnology companies in the world. It's been public since the 1980s. I picked this stock back in our old Rule Breaker portfolio. For those who remember our AOL days and early days free at fool.com, Amgen was in the so-called Fool Port, Fool Portfolio, or Rule Breaker portfolio. It was a great company I took a shine to back then. Incredibly profitable, doing good things in this world. From that portfolio, early days, fast forward now through to today when Amgen, AMGN, is the seventh-largest pharmaceutical company in the world.

Now, when did I pick this stock for Stock Advisor? Well, just last summer. Casting around for what stock to pick during a hot summer, I was probably getting ready for the beach, and I thought, "What's an easy company?" I might have mailed it in a little bit that month. "What's an easy company for me to add to Motley Fool Stock Advisor and to our members portfolios," those who wanted to buy Amgen. Happy to say the stock's up 5% since. Somewhat sad to say the market itself is up 5% since, so Amgen has just been a market performer, not a market beater, measured over that very short time frame of last June. By any meaningful long-term measure, Amgen has been a big-time winner. I expect that'll be true over the next meaningful long term, like the next 10 years.

What do I like about Amgen? No. 1: I like that it's the seventh-largest pharmaceutical company in the world. A lot of people, when they think about the age of miracles, they think about biotechnology, they think they have to go for a small company that's placing a big bet, and if it can just get through to the final stage of FDA review and get approved, you might make a ton of money. Now, we might have one company kind of like that in this sleeve, this five-stock sampler, this week. But Amgen is not that company. I like to remind people that a company like this, which has tens of billions of dollars on its balance sheet, this is a great place for a lot of biotech investors to start. So, just that sheer size for Amgen is the kind of thing that all of us should be seeking out, especially if we're going to buy our first age-of-miracles stock. This is a company with a dozen or more products focused not just on cancer, but, yes, and not just on inflammation or neurology, but, yes to both of those; cardiology as well. We're talking about a fully diversified worldwide leader, a great American company coming out of Thousand Oaks, California. This is a great company. I loved it back in the 1990s. Here we are, practically into the 2020s, and I'm still talking about Amgen, stock No. 1.

What's the second thing I like about it? How about a dividend? Yep, some of these companies actually pay dividends. Not many more of the ones we'll be covering this podcast. But Amgen pays a dividend right around 3%, maybe just short of 3%. What's a dividend? I know many of you already understand dividends, but I'm always trying to bring everybody into the fold here at Rule Breaker Investing. Just briefly, you should know that companies with a portion of their profits or their money pay that sometimes directly back out to shareholders. In a way, it's like the interest rate you get paid for holding a stock. So when I say the dividend yield is right around 3%, that means if you were to buy Amgen stock today and just hold it over the next year, and the stock stayed flat, you would still get paid on top of that 3% as a gift from the company itself, paying you a dividend to own its stock. Most of these companies that have a lot of money that can afford these dividends have a good possibility of increasing them over time. So Amgen is one of those companies. I'd like to double underline that because you don't necessarily expect that from age-of-miracles stocks. So those are two things that I like about Amgen, its sheer size and diversity, and of course, its dividend.

What's one thing to watch? Well, how about how much the company spends on research and development? This is a simple metric you can track not just for age-of-miracles companies, but for many others in other sectors. Anytime you're dealing in emergent technologies, I like to see what portion of revenues, what portion of the top-line sales, is a company putting toward research and development? The Xerox PARC, the guys who blow stuff up and labs, things that don't always work, but sometimes pay off big? What portion of its sales does Amgen spend on research and development from one year to the next? I'm happy to say it's right around 15% recently and historically. That is an outstanding measure.

Now, especially in emergent medical and biotechnology as a field, you're going to expect to see higher R&D. If you were to see that percentage start to decline over time, that's a sign that a company may be running out of ideas or feeling pressed for profits and not being willing to spend as much on testing and learning. That's the number you'd like to focus on not just for Amgen but for really any company in emerging technology. So I'm flagging that one as something to look for for Amgen. 15% of sales, that's over $3 billion for this company. That's larger than many companies' revenues, and that's how much Amgen spends each year on R&D.