Only invest in biotech stocks.

Sound crazy? Maybe, but that's what I do. I'm not fazed by their high risk or jaw-dropping volatility. That's because when biotech winners hit, they hit big. Simply put: A basket of carefully selected biotech stocks will trounce the market over the long haul.

The ultimate growth industry
Health care is a sector with a massive demographic tailwind as baby boomers age and spending on drugs and medical devices skyrockets.

Then we have many major advances coming from small-cap biotechs. Thanks to their small size, a single drug can drive tremendous increases in value for a company like this. The lengthy and expensive clinical trials required to attain FDA approval serve as a steep barrier to entry, allowing companies that cross this milestone to maintain fat profit margins for many years.

These factors combine to give us an opportunity where explosive returns are to be found.

Growth investors can't afford to ignore biotech
Consider that the top-performing U.S.- or Canada-based biotechs over the past five years have an average return of 758%. A $10,000 investment in this basket would be worth $75,800 today:

Company

Return, November 2002 to November 2007

Illumina

1,307%

Elan

1,002%

Celgene

990%

Ventana Medical Systems (NASDAQ:VMSI)

844%

MGI Pharma

698%

Alexion Pharmaceuticals (NASDAQ:ALXN)

671%

United Therapeutics (NASDAQ:UTHR)

622%

Immucor (NASDAQ:BLUD)

603%

ImClone Systems (NASDAQ:IMCL)

447%

Cepheid (NASDAQ:CPHD)

401%

Average Return

758%

Source: Capital IQ, a division of Standard and Poor's. Results exclude penny stocks.

But looking at past performance alone does nothing to help us make money now. We need to understand exactly what was creating these monstrous gains if we hope to replicate that performance over the next five years.

To help address that issue, I looked to see if there was a defining characteristic driving the performance of these small-cap biotech companies.

That defining characteristic
As it turns out, one factor is pervasive in this group: explosive revenue growth thanks to new product launches. As a group, these companies have a compound annual revenue growth rate of 49% over the past five years. This is what happens when a small biotech with no marketed products hits it big with its first drug launch.

Consider Celgene, a biotech whose gains have come on the back of two approved cancer drugs, Thalomid and Revlimid. The company just reported a phenomenal quarter, with revenue growth of 43% pushing the top line to $350 million. This year, Celgene will easily break the $1 billion annual sales barrier, putting it in an elite class of biotechs. It's no wonder this stock has increased tenfold in five years.

United Therapeutics has also done very well for itself in recent years. This biotech had just $30 million in revenue in 2002, nearly all of which came after the FDA approved its pulmonary arterial hypertension drug, Remodulin, in May of that year. Since Remodulin's approval, the company has done a great job in delivering top-line growth. Long-term shareholders have been richly rewarded with a stock price that has jumped from $15 to more than $100.

The Foolish bottom line
The returns above show that as investors, we need to be there before drug approvals happen if we want to lock in the big gains. This means we need to find high-quality drugs early in clinical development, before their potential is fully recognized by the rest of the market.

As a biotech analyst on the Motley Fool Rule Breakers team, I focus on finding small-cap biotech companies on the verge of releasing new products. More importantly, I want to find them before anyone else does. If you'd like to take a look at the biotech companies I'm recommending today, click here to join Rule Breakers free for 30 days.

This article was first published on May 17, 2007, as "Start Making $67,000 Today." It has been updated.

Fool analyst Charly Travers really does only own shares of biotech companies -- though he doesn't have a position in any company mentioned here. The Motley Fool has a disclosure policy.