The Economist and others have argued that declining rates of marriage in developing countries is due to gender imbalances resulting from a preference for male children. Matt Phillips looked at statistics which indicated that this was not the case:

• In France after World War 1 there were 40% fewer single males than females.
• Yet rates of marriage were higher than ever – French women simply adjusted by marrying younger French men.
• Couples were also more willing to engage in cross-class relationships.
• Therefore it seems that rates of marriage don’t depend as much on having roughly equal numbers of single males and females.
• War, in general, seems particularly good at boosting the appetite for marriage:

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Source: Quartz