Stocks aren't like children. It's not a problem at all if you don't love each stock in your investment portfolio equally. You can have favorites without even the smallest amount of guilt.

In my case, Celgene Corporation (NASDAQ:CELG) stands out among all the stocks that I own. It's so high on my list, that I named it a few months ago as the one stock I'd buy if I couldn't buy any other. Why do I love Celgene so much? Here are the three biggest reasons.

Male and female scientists looking at monnitor

Image source: Getty Images.

1. Revlimid and cohorts

It's hard to overstate just how strong of an asset Celgene has with Revlimid. The drug dominates the blood cancer landscape, treating the "three Ms": multiple myeloma, myelodysplastic syndromes (MDS), and mantle cell lymphoma. More indications could be on the way. Celgene is also evaluating Revlimid in treating several other types of lymphoma.

Revlimid is a big blockbuster already, generating sales of $3.9 billion in the first half of 2017. However, the next several years should be even better. Revlimid is on track to be the world's top-selling cancer drug by 2022, pulling in more than $14 billion annually. 

While Celgene depends heavily on Revlimid for its total revenue, the biotech also has several other rising stars. Multiple myeloma drug Pomalyst and autoimmune disease drug Otezla are also blockbuster success stories. Cancer drug Abraxane could hit the $1 billion sales market this year. Peak sales for newly approved acute myeloid leukemia drug Idhifa could surpass $500 million annually. 

2. A pipeline ready to roar in the '20s

Eventually, even the best drugs lose their patent exclusivity and sales begin to decline. That's why it's important for drugmakers to have strong pipelines to deliver new products that can fill the shoes of the past winners. Celgene's pipeline appears to be ready to roar, particularly in the next decade.

The biotech expects to receive approval for 10 current pipeline candidates by 2022 that could generate peak annual sales of $1 billion or more. Celgene thinks four of those experimental drugs could bring in annual sales of $2 billion or more.

Ozanimod is at the top of the list. Celgene hopes to win regulatory approval next year for the drug in treating multiple sclerosis next year. Ozanimod is also being evaluated in a late-stage study for treating ulcerative colitis and a phase 2 study for treating Crohn's disease. Another inflammation and immunology candidate also has great prospects. Mongersen is currently in late-stage studies targeting treatment of Crohn's disease and ulcerative colitis. 

Celgene isn't looking to relinquish its leadership position in blood cancer, either. Promising experimental drug luspatercept appears to be on track for potential approval in treating beta-thalassemia by 2019.

3. Ability to rinse and repeat

As much as I like Celgene's current product lineup and pipeline, what really makes the company a star in my view is that it should be able to keep its momentum going for a long time to come. Why? Celgene has built a stellar in-house research and development capability -- but it has also created an impressive network of partnerships. These partnerships give Celgene a much larger pipeline than it could have on its own at a relatively low cost.

This network of partners has also seen one success recently. Celgene and Agios (NASDAQ:AGIO) won approval for Idhifa earlier this month. The two companies are also collaborating on another experimental leukemia drug, AG-881. 

Celgene's list of partners includes nearly 50 companies -- and the count is growing. In July, Celgene announced a deal to collaborate with Chinese biotech BeiGene (NASDAQ:BGNE) on PD-1 inhibitor BGB-A317.

It's not just partnerships, though. Celgene has demonstrated an ability to make smart acquisitions as well. The company gained ozanimod through its 2015 buyout of Receptos. Abraxane was added to its lineup with the 2010 acquisition of Abraxis. 

Over the past five years, Celgene has been by far the best-performing big biotech stock (those with market caps topping $50 billion). It's definitely been one of the biggest winners in my portfolio. I expect the company's ability to "rinse and repeat" will make Celgene a great stock to own for years to come.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.