Photo: adman_as (flickr)

How can you help the world's neediest people when you don't even know they exist?

Take Rio de Janiero's sprawling slum settlements, known as favelas. They contain maybe one-third of the city's population, but no one really knows for certain, and the official counts are probably too low. When you consider similar situations worldwide, there are perhaps more than a billion people whose governments have no official record of their existence, says Melanie Edwards.

Her company, Mobile Metrix, hires and trains local teenagers — in Brazil and other developing countries — equips them with handheld computers and sends them door-to-door to get lifestyle information on their neighbors via a 100-question survey.

The idea is that aid organizations, governments and corporations essentially make decisions on where to spend money based on unreliable numbers. Enter Mobile Metrix, which says it "connects the uncounted poor with companies and nonprofits that can meet their needs."

Part of the reason the model is viable is because Mobile Metrix is able to persuade corporations to support its work. When a dengue epidemic infected nearly 250,000 in Rio de Janeiro earlier this year, for example, Mobile Metrix teamed up with Johnson & Johnson to provide favela residents with anti-mosquito repellent and doorstep tips on malaria prevention.

Edwards says each young Mobile Metrix "agent" is paid better than a drug pusher on the streets of Rio and can gain professional skills and a sense of dignity.

"These are capable, untapped human resources. By believing in them, we dignify them and they dignify themselves," Edwards told Rob Katz of NextBillion.net. "We see our employees step into their power — to transform themselves and their community."

Condoms prevent transmissions of disease, and could be key to population control. Photo: Rampant Gian (flickr)

CIA director Michael Hayden recently identified one of the biggest threats facing the U.S., something that occurs over 215 million times a day — sex.

“Population is the essential multiplier for any number of human ills," Hayden said recently. He said overpopulation in the poorest parts of the world is causing global political instability and extremism, climate change, and the food and fuel crises.

In the 1970s, environmentalists frequently discussed the problems of overpopulation, but in the last 30 years, rigid population control has been condemned.

Robert Engleman, vice-president at the Worldwatch Institute and author of the new book More: Population, Nature and What Women Want, says that after China's controversial one-child policy, "Environmentalists came to realize how complicated and sensitive this issue was.”

As food and fuel prices rise, so do concerns that the planet’s limits are finite. Population growth has slowed in developed countries, but is still rising in much of the developing world. With climate change forcing a fresh look at overpopulation, Engleman’s new book argues that “the key to limiting population growth is to give control over procreation to women.”

What Engleman is suggesting is not feminism, it’s just common sense. He says that even in societies with traditionally large families, when women gain control over family sizes with contraception access, birth rates shrink.

Fifty-year-old Linganni, who earns $2.50 a week sweeping streets in Burkina Faso, would certainly agree that too many children and not enough food is a problem. In an article that discusses how the food crisis is hitting women the hardest, The Washington Post describes how her 25 children share one meal a day. And Linganni always eats last.

In his recent article "What Condoms Have To Do With Climate Change", Time's Bryan Walsh suggests the best policy for the U.S. would be “vigorous foreign aid that helps make contraception safe, reliable and accessible in every country — too often women in the developing world who want to use contraception, can't get it.”

Contraceptive aid from the U.S. may be a difficult sell, considering that Americans are still obsessing over abstinence-only sex education and holding father-daughter purity balls. And around the world, contraception is often taboo, and the decision whether to use it is up to the man.

One solution is to support forms of contraception that give women control and are invisible to men, like the Pill or IUDs. But whatever the approach, women need to have control over the number of kids they have. Population control will only happen, Engleman reminds us, when "women are in charge."

Photo Credit: 3pom (flickr)

Technological advances have significantly impacted India's recent growth. But one technology may be causing more harm than good.

India is experiencing an alarming rise in sex-selective abortions. As the middle class has grown, more pregnant women are able to afford ultrasounds. One result is that many couples are choosing to abort female fetuses. Traditionally, boys are preferred over girls — they carry on the family name, can more easily find paid work, and don’t require expensive dowries. Even though India is becoming increasingly modernized, these traditional values remain intact.

The numbers tell the story: In 1981, India had 962 girls for every 1,000 boys. In the 2001 census, the ratio was 927 to 1,000. Indian Prime Minister Manmohan Singh recently called the problem a "national shame."

Indian society is starting to experience the repercussions. With fewer available women to marry, some Indian men are resorting to buying their brides from poor communities outside their own, the BBC reports.