Investors interested in stocks from the Medical - Biomedical and Genetics sector have probably already heard of Alexion Pharmaceuticals (ALXN) and Techne (TECH). But which of these two stocks is more attractive to value investors? We'll need to take a closer look to find out.We have found that the best way to discover great value opportunities is to pair a strong Zacks Rank with a great grade in the Value category of our Style Scores system. The proven Zacks Rank emphasizes companies with positive estimate revision trends, and our Style Scores highlight stocks with specific traits.Right now, both Alexion Pharmaceuticals and Techne are sporting a Zacks Rank of # 2 (Buy). The Zacks Rank favors stocks that have recently seen positive revisions to their earnings estimates, so investors should rest assured that both of these companies have improving earnings outlooks. But this is just one factor that value investors are interested in.Value investors are also interested in a number of tried-and-true valuation metrics that help show when a company is undervalued at its current share price levels.The Value category of the Style Scores system identifies undervalued companies by looking at a number of key metrics. These include the long-favored P/E ratio, P/S ratio, earnings yield, cash flow per share, and a variety of other fundamentals that help us determine a company's fair value.ALXN currently has a forward P/E ratio of 13.14, while TECH has a forward P/E of 60.36. We also note that ALXN has a PEG ratio of 0.88. This figure is similar to the commonly-used P/E ratio, with the PEG ratio also factoring in a company's expected earnings growth rate. TECH currently has a PEG ratio of 2.87.Another notable valuation metric for ALXN is its P/B ratio of 3.24. The P/B ratio is used to compare a stock's market value with its book value, which is defined as total assets minus total liabilities. For comparison, TECH has a P/B of 11.73.These metrics, and several others, help ALXN earn a Value grade of B, while TECH has been given a Value grade of D.Both ALXN and TECH are impressive stocks with solid earnings outlooks, but based on these valuation figures, we feel that ALXN is the superior value option right now. Breakout Biotech Stocks with Triple-Digit Profit Potential The biotech sector is projected to surge beyond $775 billion by 2024 as scientists develop treatments for thousands of diseases. They’re also finding ways to edit the human genome to literally erase our vulnerability to these diseases. Zacks has just released Century of Biology: 7 Biotech Stocks to Buy Right Now to help investors profit from 7 stocks poised for outperformance. Our recent biotech recommendations have produced gains of +50%, +83% and +164% in as little as 2 months. The stocks in this report could perform even better.See these 7 breakthrough stocks now>>Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report Alexion Pharmaceuticals, Inc. (ALXN): Free Stock Analysis Report BioTechne Corp (TECH): Free Stock Analysis Report To read this article on Zacks.com click here.