Help a poor woman stay in school, a recent study found, and her children are more likely to survive.

Help a mother earn a couple extra dollars, and her kids will get a better education.

Give a woman a loan and, more than a man, she tends to repay it.

Conversely, let a mother suffer depression and family members are liable to go hungry.

Let a mother die soon after giving birth and her child is probably going to pass away within a month.

Empowering marginalized women is of course a fundamentally good thing to do. Gender equality gives women the rights they deserve. At least since 1990, when Amartya Sen published his landmark essay “Missing Women,” about how discrimination leads to tens of millions of premature deaths, aid and development organizations have pushed to ensure that women get a fair shake.

What has become especially clear in the last decade or so is that helping marginalized women leads to disproportionately good things. Women, more than men, tend to pay forward investments in their well-being—a truth variously dubbed “the double X solution” or “the girl effect” or a “double dividend.”

“More and more, the most influential scholars of development and public health—including Sen and Summers, Joseph Stiglitz, Jeffrey Sachs, and Dr. Paul Farmer—are calling for much greater attention to women in development,” wrote Nicholas Kristof and Sheryl WuDunn in their 2010 bestseller Half the Sky. Now everywhere from universities to Goldman Sachs, tiny charities to the United Nations, women’s development is seen as a centerpiece, if not the key, to society’s development.

Partners In Health has been a leader in this movement. “We’re probably one of the largest employers of women in a lot of the places we work,” says PIH Chief of Nursing Sheila Davis. From the hilly slums of Lima, Peru, to the wooded townships of Siberia, Russia, PIH employs thousands of women, in positions that range from community health worker to nurse and doctor. The women help heal the sick, but they also do more. Local staff in Chiapas, Mexico, for example, showed a whole town that a woman’s work is not just in the home, paving the way for other women to get jobs.

PIH clinicians consult, diagnose, and treat a lot of women, as well. “Maternal health is a major focus in many of our sites,” says Davis. In all 10 countries that PIH supports, local staff help women get prenatal check-ups and medication to prevent mother-to-child transmission of HIV, if needed. In Lesotho, PIH has built waiting homes near health clinics, so pregnant women living far away can rest easy before going into labor. (A new one opens in Haiti in December, followed by one in Sierra Leone in January.) When it comes to delivery, women have access to trained midwives and, if complications arise, they are referred to a nearby facility for life-saving procedures such as cesarean sections. Afterward, women are able to return home to care for their families.

Many other programs address important issues. PIH cares for women with mental health and other non-communicable diseases, and helps women plan whether and when they have children. In Haiti and Rwanda, PIH offers oncology care for women with breast cancer, including mastectomies and chemotherapy treatment.

Everywhere they work, PIH staff are committed to keeping women healthy—in part because strong women tend to make everyone stronger.