In the letter — and in several videos released with the letter — the Gateses note that Africa, with a median age of 18, is the "youngest" continent and that the annual number of births is rising in the poorest regions of sub-Saharan Africa. But if countries commit "to investing in their young people," especially through quality health care and girls' education, writes Melinda Gates, "the region could double its share of the global labor force by 2050, unlocking a better life for hundreds of millions of people."
The Gateses also note that the world is on track to double its building stock by 2060 — the equivalent of building a New York City every month — and that the process of manufacturing building materials such as steel and cement contributes significantly to climate change. "[I]f we're going to solve climate change," writes Bill Gates, "we need to get to near-zero emissions on all the things that drive it — agriculture, electricity, manufacturing, transportation, and buildings." "Part of the solution," Gates adds, "is to invest in innovation in all five sectors, so we can do these things without destroying the climate."
Another "surprise" for the couple was the discovery that at-home DNA tests can be used not only to solve crimes but to help prevent premature birth by identifying women with one of six genes that are linked to risk of preterm labor. Despite such discoveries, however, it is not known why African-American women deliver prematurely more often than African women who immigrate to the U.S. "One theory," writes Melinda Gates, "is...that the racism and discrimination African-American women have faced their whole lives leads to stress that damages their health." According to Bill Gates, the problem is compounded by the fact that "data can be sexist," and that there is a dearth of data about women and girls, which in turn prevents in-depth study of issues that affect women and girls, "block[ing] progress for everyone."
Other areas highlighted in the letter include interventions that help young people improve their impulse control and navigate tense situations, improving their chances of staying in school and out of trouble; the "nationalist case for globalism" — including the idea that foreign aid focused on strengthening health systems increases stability abroad and security at home; the importance of affordable next-gen toilets — not only for the purposes of better sanitation and health but also as a way to improve women's safety and girls' access to education; the adoption of engaging digital curricula in classrooms across the United States, as well as the role of online learning in making college more affordable and accessible; and the role of mobile technology in enabling the world's poorest women not only to access services and opportunities but also "to change social norms and challenge the power structures that perpetuate gender inequality."
"We get asked a lot these days whether we're still optimistic about the future," the Gateses write. "We say: Absolutely. One reason is that we believe in the power of innovation. But an even bigger reason is that we've seen firsthand that for every challenge we've written about in this letter, there are people devoting their ideas, their resources, and even their lives to solving them."