Education and empowerment of women through financial training.
It is well enough documented in social studies and government reports that there is a negative correlation between the number of children per family and the educational level of women in a household.
Saddam Hussein, hardly at the forefront of the fight for women's equality of opportunity, found this out to his cost, I believe, back in the day. He was embarassed about the level of illiteracy rates shown for the country, so decreed that women should attend basic educational classes, to learn how to read and write (and raise the country's standing internationally, etc. - maybe it was for more aid for all I know).
If I recall correctly, initial resistance to the idea was smashed when men refused to allow their women out to the schools via threats to cut off utility supplies like water to the home.
Unfortunately, their government discovered an alarming trend as a result of this policy: the birth rate decreased. The government drive was stopped.
Educate women, and you educate future generations.
It's only by providing that, plus freely available contraceptives, telling religious leaders to fuck off with their rhetoic, than this planet has any hope of sustaining our race in the luxury to which the western world has become accustomed to.