Picking individual stocks is a challenge, especially when the stocks are in emerging industries where you're not sure which companies will get ahead of the pack. A potential way to meet that challenge is to invest in exchange-traded funds (ETFs) for that industry. An ETF not only allows you to spread out your risk across several stocks, but it also takes the pressure off having to make successful individual stock picks.

For example, you may be confident that biotech stocks are going to rise in the future with more medical innovation seemingly inevitable. Or you know in your heart that robotics is the next big thing and is due to take off. But predicting which individual companies will succeed in these sectors is no easy task. By investing in ETFs that specialize in these industries, you can potentially set yourself up for some strong gains, without taking on significant risk to do so.

The SPDR S&P Biotech ETF (XBI) provides investors with an excellent way to invest in biotech, while the Robo Global Robotics and Automation Index ETF (ROBO -1.12%) offers exposure to companies working on next-gen technologies. Let's take a closer look at these two ETFs.

1. SPDR S&P Biotech ETF

The SPDR S&P Biotech ETF is made up of companies in the biotech sector. It has a mix of small-, mid-, and large-cap stocks. At a relatively modest gross expense ratio of 0.35%, the fund isn't expensive to own and can give investors some terrific diversification.

There are more than 150 holdings in the fund. The largest component is clinical-stage biopharmaceutical company Madrigal Pharmaceuticals, which accounts for less than 4% of the ETF's total weight. No other stock even makes up 2%. The fund averages a price-to-earnings multiple of less than 14 -- lower than the S&P 500 average of 19. 

Even with the sell-off in growth stocks over the past year, the SPDR S&P Biotech ETF is up around 172% over the past decade, in line with the broad S&P 500 performance of 170%. But that's with growth stocks struggling. Once the bear market ends, the biotech-focused fund could begin comfortably outperforming the S&P 500, as it has done in the past.

2. Robo Global Robotics and Automation Index ETF 

Investing in robotics seems like a no-brainer given that every industry in the world can benefit from automation and machine learning. Manufacturing, in particular, is an area in which companies can achieve significant gains. According to analysts from MarketsandMarkets Research, the industrial robotics market will grow at a compound annual growth rate of 14.3% until 2027, when it will be worth $30.8 billion. And in the longer run, the opportunity could be even greater.

Robotic-assisted surgery is a promising case in point. Intuitive Surgical, a top company in that space, happens to be one of the top holdings in the Robo Global Robotics & Automation ETF. As with the biotech fund, there isn't much exposure to one single stock. The largest holding, Japanese company Harmonic Drive Systems, which makes parts that are used in robots, makes up roughly 2%. With 80 stocks, however, this ETF is smaller than the biotech fund, which may not be all that surprising considering the robotics opportunity is in a relatively early stage of development.

Since its inception in 2013, the ETF has doubled in value, performing a bit worse than the S&P 500, which is up 131% during that time frame. But this is still the early phase of what's likely to be a tremendous growth opportunity. If you're bullish on next-gen technologies and aren't all that familiar with robotics companies and businesses focused on automation, the ETF could make for a great investment to buy and hold. At 0.95%, its expense ratio is a bit high, but given the fund's specialization and its great returns already, the cost could prove to be well worth it in the long run.