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Gifting children or grand-children stocks while they are young can be a wonderful idea, as watching a winning stock go up can help to kick-start the love of long-term investing. With the benefit of having decades of time on their side, giving your children or grand-children a stock that can compound for years into the future will certainly go a long way toward helping them become financially independent one day.

We reached out to our team of Motley Fool contributors and asked them to share a stock that they believe is a great choice for long-term buy and hold investing.

George Budwell: When contemplating stocks to buy for extended periods of time such as 20 years or more, I think it's important to go with large companies with stable operating histories, a clear vision for the future, and a sustainable dividend payout.

The British pharma giant AstraZeneca (NYSE:AZN) looks, to me, like it embodies all of these desired traits. In its present form, Astra has been in business for going on 24 years at this point and is the tenth largest prescription pharma company in the world in terms of market capitalization. 

Management has also been upfront about the direction of the company moving forward. Specifically, Astra is in the process of building out a formidable presence in high growth markets such as diabetes care and immuno-oncology. By all accounts, these two key therapeutic areas are expected to generate above average growth over the long-term. In other words, these two particular markets that management has identified as being key growth drivers for the company aren't about to evaporate overnight.

Although Astra's quarterly dividend payment has fluctuated in value over the last 15 years, the drugmaker has never suspended its payout during that time period, and management appears committed to continuing this trend for the foreseeable future.

The downside risk, though, is that management is banking heavily on its huge immuno-oncology pipeline to help return the company to growth by 2018. As experimental cancer drugs in general have a terrible track record when it comes to meeting their primary endpoints in late-stage trials, there is a good chance that Astra's stated goal won't be met. 

But the sheer size of Astra's effort in cancer immunotherapy -- that includes 16 mid- and late-stage studies already in progress -- gives the company a decent shot at bringing at least one major new oncology product to market within the next few years. 

All told, Astra is a large cap, dividend-paying pharma stock that should provide stable growth for decades to come. 

Todd Campbell: Investments that can be left untouched for decades offer an investor the flexibility to ride out short term bumps and bruises. Because of that, investors might want to consider stashing away for their young ones a high growth company such as Celgene (NASDAQ:CELG).

Celgene is already a major player in healthcare, marketing a slate of top-selling and fast-growing therapies, primarily for treating cancer. Its top seller is Revlimid, a $5 billion plus therapy for multiple myeloma that's the go-to second-line treatment in the indication. Celgene also markets the pancreatic cancer drug Abraxane, the third-line multiple myeloma drug Pomalyst, and the autoimmune disease drug Otezla. Combined, those drugs are expected to generate sales and per-share profit of at least $9 billion and $4.75, respectively, this year.

That's impressive, but its Celgene's willingness to invest heavily for future growth that I find most intriguing.

Recently, the company inked a $1 billion deal to collaborate with Juno Therapeutics on next-generation cancer immunotherapies and a $7.2 billion deal to acquire Receptos to get its hands on a late stage oral drug for multiple sclerosis. Additionally, the company has a variety of other collaborations under way, any of which could produce a future top-seller.

Overall, Celgene believes that its sales could eclipse $21 billion by 2020 -- a more than doubling in the next five years. For that reason, this is one of my favorite stocks to buy and hold for the long haul.

Brian Feroldi: With a multi-decade time horizon in mind, one healthcare stock that I think is a great choice for young investors is Alexion Pharmaceuticals (NASDAQ:ALXN). The company is profitable, growing quickly, and has a pipeline full of potential that could power it higher for years into the future.

Alexion has a focus on finding drugs that treat very rare diseases, and its first approved drug, Soliris, was a monster hit. Soliris treats two ultra-rare disorders -- paroxysmal nocturnal hemoglobinuria and atypical hemolytic uremic syndrome -- and single-handedly brought the company to profitability. The company also recently scored two regulatory wins that could significantly accelerate its growth rate and at the same time diversify its revenue base away from dependence on Soliris.

These two new drugs, Kanuma and Strensiq, have been cleared for sale in Europe, and Strensiq just received FDA approval in the United States as well. Each of these drugs fit nicely into the company's area of expertise -- treating ultra-rare diseases -- and analysts are currently projecting that both drugs could reach blockbuster status.

Beyond these two newly-approved drugs, Alexion has three other drugs in advanced clinical development, and another 11 in early or preclinical trials, so when given enough time the company should certainly be able to create a few more hits. The company has also shown a willingness to acquire other drugs when they fit into the company's ultra-rare disease strategy, as it did earlier this year when it paid $8.4 billion to acquire Synageva (and thus Kanuma).

Alexion's shares are a bit pricey right now, trading around 54 times trailing earnings, but with a multi-decade time horizon I think Alexion's growth prospects should allow it to continue to out-perform the market, making it a great stock to consider buying for your kids or grandkids.

Brian Feroldi has no position in any stocks mentioned. George Budwell owns shares of Celgene and Juno Therapeutics. Todd Campbell owns shares of Celgene. The Motley Fool owns shares of and recommends Celgene. The Motley Fool recommends Juno Therapeutics. 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.