The philanthropic duo give their two cents or rather $200-million on how to deal with the world's inequalities.
But seemingly only when you're a man - there's more data in the world about men, they own more mobile phones than women and they're not as vulnerable when it comes to, well "heeding nature's call" out in the open.
From cow farts to the sexist data crisis, the Bill & Melinda Gates Foundation's annual letter highlights some of the world's greatest inequalities, and they give their two cents or rather $200-million on how to make them vanish.
Here are five things the philanthropic couple say that could make the world a better place.
1. Invest in young people, especially young women, to make countries healthier - and wealthier.
So where do the world's young people live? Africa. About four out of 10 people on the continent were under the age of 15 in 2017, United Nations statistics show.
Countries prosper when young people do, especially when they have access to high-quality health and education services. And young women are an economic tour de force. If every young woman had quality healthcare and education, their collective lifetime earnings would increase to $30-trillion, a 2018 World Bank report argues.
That's more than the annual gross domestic product of the United States, the World Bank says.
But it doesn't just make women and nations wealthier, it saves lives. The United Nations Educational, Scientific and Cultural Organisation (Unesco) argues that educating young women in low- and middle-income countries would slash child mortality rates by half.
And when we say "education", we mean reading, writing and comprehensive sexual and reproductive health rights information, Melinda Gates tells Bhekisisa.
"It's really important to provide young people with age-appropriate, accurate, culturally relevant information about their reproductive health so that they can safeguard their health and plan for their futures."
2. Listen, solar panels are great... but let's talk about manufacturing. And cow farts.
When we talk about health, we should also be talking about the environment and stopping climate change isn't just buying a solar panel and calling it a day.
There are five big challenges to climate change; agriculture, electricity, manufacturing, transportation and buildings, Bill Gates says.
Electricity production is only responsible for a quarter of all greenhouse gases while - wait for it - flatulent cows - and other emissions related to forestry and land use are responsible for 24% of all gasses emitted around the world, the United Nations Intergovernmental Panel on Climate Change argued in a 2014 report.
If we're serious about stopping climate change, we need near-zero emissions on all things that drive it. It's unrealistic to ask the world to stop using electricity or farm cows so part of the solution has to be innovation and get media coverage to match the gravity of the situation, Bill argues.
3. Speaking of innovation, it's time to bring sewage treatment back to where it belongs: The home.
The World Health Organisation estimates that 2.3-billion people lack access to basic sanitation.
Going to the bathroom outside is dangerous for several reasons: First off, there's the likelihood that sewage will seep into water sources and spread disease.
But open defecation can also be unsafe especially for women and children because of everything from crime to dangerous animals.
Just build more toilets, right? Not so much. Regular toilets require working sewage systems that many countries don't have, and that would cost too much to build.
The solution lies in a new kind of loo that can kill germs and turn waste into fertilizer. After toilet innovators met last year at the foundation's Beijing toilet fair, Bill says several companies are ready to bring new loos to the market. With a cash injection of $200-million for manufacturers, the foundation is hoping to make them affordable.
Read more: A new loo: Gaze into the toilet bowl of the future
4. The world needs to produce more data about women. It would help if it wasn't sexist.
"How much income did women in developing countries earn last year? How much property do they own? ... I don't know. Neither does anyone else. The data just doesn't exist," Melinda says.
Data informs policy but the world can't make better policies to empower women if it can't quantify the extent of their discrimination.
She says there's not just a gap in data, but that numbers that do exist are sexist. Why? Because she says that in many countries information is only confined to documenting reproductive health, in which women are only seen as wives and mothers. The foundation has invested more than $80-million to help fill in the data gaps.
5. And while we're on the subject... you know what else is sexist? Mobile phone ownership. We need to put cell phones in the hands of the world's poorest women.
In low- and middle-income countries, more men than women own a mobile phone and failing to address this gap will exclude women from an increasingly digitised society, industry lobby group Global System for Mobile Communications argues.
The divide exists for a variety of reasons but cost, literacy and social norms are the most likely drivers, Melinda argues.
With this in mind, the foundation partnered with the Harvard Kennedy School in the United States to find solutions to the social norms barrier.
So what happens when we enable women with this basic mobile technology?
She explains: "For the world's most marginalised women, a mobile phone doesn't just make their old life more convenient, it can help them build an entirely new life. That's because connectivity is a solution to marginalisation."
Disclosure: The Bill & Melinda Gates Foundation is one of the Bhekisisa Centre for Health Journalism's donors.