Researchers and workers in the field of development have known for several decades that the best and surest way to reduce birth rates is to improve the condition of women. To give them more opportunities, more education, and more power over their own lives. When women can choose, they choose to have fewer kids. In an overpopulated world, that is a good thing.
The irony is that societies that respect women and treat them fairly are losing the demographic contest. They are having fewer babies. Too few. The population of progressive, liberal countries is declining. Societies, or social groups, that don't recognize the equality of women-- in fact, treat women as little more than male property-- are booming. The Middle East has the highest birth rates in the world. Iraq, for instance, has 4.5 births per woman, compared to the world average of 2.5 (2.1 is needed to maintain population). Iraq's population is expected to triple in size by the end of the century, to over 100 million. In Yemen, another country troubled by civil war, the birth rate is even higher.
The 'Arab Spring' is fueled by the stagnant economies and booming populations of the Middle East and North Africa. Their youthful societies-- especially when so many youth are underemployed-- are part of the reason the region is so violent. It is not a coincidence that Yemen and Iraq-- the two countries with the highest birth rates in the region-- are embroiled in civil war. (Yes, the American invasion is also to blame in Iraq.) Improving women's rights is vital: it would reduce the population surge, release some of the economic pressure, and lead to more stable and peaceful societies. But the politics of the region is moving in the other direction, towards less liberal, more 'Islamic' attitudes towards women. Women are losing what few rights they had. This will only make the population crisis worse.
Meanwhile, birth rates in North America, Europe, Australia, Japan, China, and other countries where women have equality are declining. In Latin America, too, it is dropping. In Brazil, it is now only 1.9 births/woman, about the same as the U.S. rate. Without immigration, Brazil, like the developed world, will begin to decline in population. Why are birth rates falling in Brazil? Urbanization and less poverty are factors, but the main reason is that young Brazilian women are better educated and more assertive than older generations of women.
Perhaps this is why matriarchal societies of the past-- assuming they are not mythical-- lost out to patriarchal societies. They simply did not have as many children. If so, we are seeing history repeat itself in this century.