(FORTUNE Magazine) – I've decided to add a small component of high risk to my IRA, and I can't think of anything riskier than to buy a mutual fund that invests in nothing but biotechnology. I'm not talking about some watered-down fund that mixes in other health-care-related stocks to soften the blow of biotech's eventual blowups. What I want is a pure, high-octane fund that can get full-throttle gains from the next biotech boom.

If the phrase "biotech boom" causes your eyebrow to arch or your lips to quiver, no wonder. Right now biotech is a bust--as an investment, that is. The Amex biotechnology index, a group of 17 stocks created in 1991, is down 38% this year, vs. the S&P 500's 21% decline. And that's just why it caught my eye.

I've written about biotech companies on and off since the late 1980s. Because any individual bio stock can (and probably will) melt down at some point, snookering even sophisticated investors, buying a basket of them has always been the smartest tack. But a still better idea is to buy that basket when nobody else wants it, and wait. With my time horizon of ten to 15 years, I'm willing to bet that at some point biotech stocks will be driven to dizzying heights--perhaps even higher than the sector's last boom, when the Amex biotechnology index, for instance, leaped 62% in 2000. (The S&P dropped 10% that year.)

Here's why. With biotech, all it takes to spark a buying frenzy is one major breakthrough in the quest to cure cancer, AIDS, or another disease. And unlike regular technology, which goes through cycles, biotech doesn't create a commodity that can quickly be leapfrogged by a competitor. "These three- to five-year boom-to-bust cycles have been in biotech for 20 years," says John Freund, managing director at venture capital firm Skyline Ventures, which invests in biotech stocks. But if you look back, he adds, even after each cycle of bust the sector has held sustainable market gains. "That reflects that this is now a real industry with real drugs," he says. Drugs like Genentech's Herceptin for breast cancer, Amgen's anemia-fighting Epogen, and Rituxan, an innovative cancer drug developed by IDEC Pharmaceuticals.

So which fund to buy? There are now only a dozen or so that appear to be invested exclusively in biotech--unlike the sector's early go-go days when a new one was being created every minute. Schwab, the caretaker of my IRA, lists only a handful of funds. There's also the American Stock Exchange-traded Biotech HOLDRS, a passively-managed basket of 20 stocks. This lack of options, thankfully, makes it easy to whittle down the choices, especially considering my criteria: My fund pick has to be actively managed (that dings the Biotech HOLDRS), and the manager has to be seasoned enough to have guided the fund through the previous boom and bust.

That pretty much narrows it down to the Fidelity Select Biotechnology fund, the Pimco RCM Biotechnology D fund, and the Franklin Biotechnology Discovery fund. All three have a good mix of large and small names and similar track records. However, Fidelity's manager, Andraz Razen, was just an analyst before taking the job earlier this year. I'll let him learn to manage on someone else's dime! (With my luck, his fund will be the biggest winner of all.)

That leaves the Franklin and Pimco funds, and choosing between them is a gut wrencher. Both funds, according to mutual-funds research firm Morningstar, are considered volatile (duh!) and (reading between the lines) are only for nuts like me. Franklin's lead manager, Evan McCulloch, has been with the fund since 1997, mostly with a co-manager who left after helping guide the fund to a 98% gain in 1999 and a 47% rise in 2000. (So far this year it's down 39%, in line with the Amex biotech index.) The Pimco offering has fallen a comparable 37% this year but shot up an IRA-goosing 111% in 1999 and 82% in 2000. Michael Dauchot, who became the Pimco fund's lead manager in 2001, was a co-manager during that period. He has also co-helmed its biotech-rich sibling fund, Pimco RCM Global Health Care (which rose 73% in 2000), since 1999. Furthermore, the Pimco biotech fund is a more active trader than the Franklin fund, which means it is more likely to cut its losses faster. But the real kicker? The Pimco fund is load-free, vs. the fat 5.75% upfront charge for Franklin. (I'd pay the load for a fund that was the clear-cut best of the bunch, but why shell out the cash if you don't have to?)

Buying, though, is always easy. The trick will be figuring out when the next boom cycle is topping out so I can sell. Hopefully, when the time comes, I'll know the difference between bulls, bears, and pigs--especially the genetically altered kind.

Herb Greenberg is a senior columnist for TheStreet.com. Questions? Comments? E-mail him at herb.greenberg@thestreet.com.