More broadly, disadvantaged workers can be bad for business. Absenteeism, low productivity, inadequate training, and high turnover make for higher labor costs and lower profits.

Multinational companies know they’ll have trouble convincing an openly gay executive to accept a transfer to a country that is LGBT intolerant. Tour operators steer LGBT tourists away from hotels and attractions in unfriendly countries.

The numbers back up these contentions. Even though the LGBT community is a relatively small percentage of any country’s population, the economic costs from unequal treatment can add up quickly. A recent World Bank case study of the cost of stigma and LGBT exclusion in India shows how the losses could be calculated. Similar studies of gender inequality and other forms of discrimination have shown the billions of dollars lost by national economies from discrimination.

Unfortunately, data on LGBT people in India are not available to estimate the effects as precisely in that study. But my own back-of-the-envelope calculation using what we do know about the costs of discrimination and big health disparities for LGBT Indians gives us a good idea of how large the effect could be. Even with conservative assumptions that make costs low, the estimated losses to the Indian economy range from 0.1 percent to 1.4 percent of national output, a meaningful loss that no country—rich or poor—would want to bear. The bottom line: India could be throwing away more than $26 billion a year by stigmatizing LGBT people.

Luckily, there’s a way to recoup those costs: A study that I co-authored, just released by USAID and the Williams Institute at UCLA, finds that countries that treat LGBT people equally also have better-performing economies. In our study of 39 countries, we compared a measure of rights granted by each nation related to homosexuality—decriminalization, nondiscrimination laws, and family rights—to GDP per capita and other measures of economic performance.

The positive link between rights and development is clear: Countries that come closer to full equality for LGBT people have higher levels of GDP per capita over the 22 years we studied.

Even after we take into account other differences across countries that matter for GDP growth, like capital stock and international trade, we still find a strong positive effect of gay rights. Each additional right is associated with a $320 increase in per capita GDP, or about 3 percent of the average output produced by an economy. A better environment for LGBT individuals can be an attractive bargaining chip for countries seeking multi-national investments or even more tourists. On a recent trip to Peru, I talked with people in businesses, universities, and government ministries who expressed concern that because their country lags behind many other South American countries on LGBT rights, they fear they could be less competitive globally. They are right to be worried. A conservative climate that keeps LGBT people in the closet and policymakers from recognizing the human rights of LGBT people will hold their economy back from its full potential.