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Biotech stocks tend to be a risky breed, since even though they can offer investors strong returns, they usually walk hand in hand with huge volatility. To see this reality in action, look no further than the year-to-date returns of the iShares Nasdaq Biotechnology ETF (NASDAQ:IBB), an exchange-traded fund that holds a diverse collection of biotech stocks. This ETF has been a basket case year to date, as returns have ranged from up a huge 32% in July to down nearly 3% for the year by mid-October.

That kind of gut-wrenching volatility can make it feel as if investors in the space need to watch their biotech stocks at every move. To help bring some stability to the situation we asked our team of Motley Fool healthcare analysts to share a biotech stock that they feel is a bit safer than average and doesn't require constant monitoring. Have a look for yourself at the three stocks they selected, to see if any of them might deserve a spot in your portfolio.

George Budwell: I think Gilead Sciences (NASDAQ:GILD) is a great biotech stock to own for investors who don't want to constantly check up on their portfolios, because it's a fundamentally strong business, headed by one of the best CEOs in the business, John C. Martin. 

Under Martin's watchful eye, Gilead has transformed into the dominant player in both the HIV and hepatitis C drug markets. His basic strategy has been to gobble up smaller biotechs and biopharmas and then leverage Gilead's vast resources to accelerate the development of their most promising product candidates. And the results have been nothing less than spectacular. 

After acquiring Pharmasset in 2011, for instance, Gilead was quickly able to build a formidable position in the lucrative hepatitis C space by bringing Sovaldi and Harvoni to market in rapid succession. In turn, these two drugs have helped Gilead's free cash flows to rise to an astounding $18.4 billion over the past 12 months, thereby enabling management to initiate a dividend payment and significantly amp up the company's share buyback program.

While it's true that Gilead's top line is expected to stagnate over the next year, it's important to keep in mind that the company should still generate staggering amounts of free cash. What this means is that Gilead should be able to slowly build up a monstrous cash position that could be used for a variety of value-creating activities, such as paying off debt, buying other drugmakers with approved products already on the market, or simply increasing the dividend. 

Todd Campbell: There are only a few top shelf-worthy biotech stocks that will keep investors from tossing and turning at night, and I believe that Celgene Corp. (NASDAQ:CELG) is one of them.

Celgene is best known for Revlimid, the market share-leading first- and second-line therapy for multiple myeloma, but the company also markets Pomalyst, a leading third-line therapy for multiple myeloma that's growing quickly, Abraxane, which treats non-small-cell lung cancer and pancreatic cancer, and Otezla, a recently launched autoimmune drug that's shaking up psoriasis treatment because its dosed orally, rather than injected.

Altogether, Celgene expects that these drugs will allow it to record sales and per-share earnings of at least $9 billion and $4.75 this year, respectively, and that these drugs (plus potential sales from a recently acquired multiple sclerosis therapy that's in phase 3 trials) has Celgene thinking it can more than double its sales to over $21 billion in 2020. If so, then Celgene thinks it can deliver EPS that year of more than $13.

Additionally, Celgene is investing big money in collaboration and new pipeline candidates that could lead to various other drug approvals in the coming decade that could fuel even greater sales and profit growth. 

Because Celgene already has top-selling medications and it's developing a new wave of potential blockbusters, it's one biotech company that I think investors won't have to worry too much about if they own it.

Brian Feroldi: One biotech that I think investors can buy and hold for the long term without much worry is Amgen (NASDAQ:AMGN). I think it's a good choice for investors looking for a relatively "hands-off" biotech investment because it offers up a nice combination of a dependable growth, a solid dividend yield, and a below-market valuation.

Amgen has long been a cash cow thanks to hugely profitable drugs such as Enbrel and Neulasta, which, despite being on the market for years, are still showing growth. While these drugs might finally be facing some competition from biosimilars, Amgen's total sales should continue to grow at a decent clip thanks a slew of new drug launches. Amgen recently launched a handful of drugs that appear to hold blockbuster potential, such as its cholesterol-busting Repatha, chronic heart failure treatment Corlanor, osteoporosis treatment Prolia, and multiple myeloma treatment Kyprolis. With these drugs added to its current portfolio of medications, Amgen should be able to continue to grow at a good rate for years to come.

For the full year, Amgen expects to generate around $10 in earnings per share, which means its stock is trading for roughly 15 times full-year estimates, which puts it at a nice discount to the S&P 500. When you consider that Wall Street believes Amgen can grow its bottom line by more than 10% over the next five years, I think that's a perfectly fair price to pay. When you throw in a dividend that's currently yielding over 2%, I think Amgen is a great choice for investors who want a biotech stock whose every move they don't have to follow.

Brian Feroldi owns shares of Gilead Sciences. George Budwell owns shares of Celgene and Gilead Sciences. Todd Campbell owns shares of Celgene and Gilead Sciences. The Motley Fool owns shares of and recommends Celgene and Gilead Sciences. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.