On Thursday, Barclays is launching a new index and exchange-traded note (WIL) that lets retail investors buy shares — at $50 a pop — of a basket of large U.S. companies led by women, including PepsiCoPEPSICO INC. PEP 0.38% , IBMINTERNATIONAL BUSINESS MACHINES CORP. IBM 0.33% , and XeroxXEROX CORP. XRX 0.6% . This should be exciting news for anyone disappointed by the lack of women in top corporate roles. After all, female CEOs still make up less than 5% of Fortune 500 chiefs and less than 17% of board members — despite earning 44% of master’s degrees in business and management. The new ETN is not the only tool of its kind: This past June, former Bank of America executive Sallie Krawcheck opened an index fund tracking global companies with female leadership — and online brokerage Motif Investing currently offers a custom portfolio of shares in women-led companies. The big question is whether this type of socially-conscious investing is valuable — either to investors or to the goal of increasing female corporate leadership. Is it wise to let your conscience dictate how you manage your savings? And assuming you care about gender representation in the corporate world, is there any evidence that these investments will actually lead to more diversity? Here’s what experts and research suggest: Getting better-than-average returns shouldn’t be your motivation. Beyond the promise of effecting social change, the Barclays and Pax indexes are marketed with the suggestion that woman-led companies tend to do better than peers. It’s true that some evidence shows businesses can benefit from female leadership, with correlations between more women in top positions and higher returns on equity, lower volatility, and market-beating returns. But correlation isn’t causation, and other research suggests that when businesses appoint female leadership, it may be a sign that crisis is brewing — the so-called “glass cliff.” Yet another study finds that limiting your investments to socially-responsible companies comes with costs. Taken together, the pros and cons of conscience-based investing seem generally to cancel each other out. “Our research shows socially responsible investments do no better or worse than the broader stock market,” says Morningstar fund analyst Robert Goldsborough. “Over time the ups and downs tend to even out.” As always, fees should be a consideration. Even if the underlying companies in a fund are good investments, high fees can eat away at your returns. Krawcheck’s Pax Ellevate Global Women’s fund charges 0.99% — far more than the 0.30% fee for the Vanguard Total World Stock Index (VTWSX). Investing only in U.S. companies, the new Barclays ETN is cheaper, with 0.45% in expenses, though the comparable Vanguard S&P 500 ETF (VOO) charges only 0.05% — a difference that can add up over time: If supporting women is very important to you, you might consider investing in a broad, cheap index and using the money you saved on fees to invest directly in the best female-led companies — or you could simply donate to a non-profit supporting women’s causes. If you still love this idea, that’s okay — just limit your exposure. There is an argument that supporting female leadership through investments could be more powerful than making a donation to a non-profit. The hope is that if enough investor cash flows to businesses led by women, “companies will take notice” and make more efforts to advance women in top positions, says Sue Meirs, Barclays COO for Equity and Funds Structured Markets Sales in the Americas. If investing in one of these indexes feels like the best way to support top-down gender diversity — and worth the cost — you could do worse than these industry-diversified offerings. “Investing as a social statement can be a fine thing,” says financial planner Sheryl Garrett, “though you don’t want to put all of your money toward a token investment.” Garrett suggests limiting your exposure to 10% of your overall portfolio.