When it comes to identifying the causes of the two major economic problems facing the developed world — rising inequality and a slowdown in economic growth — sex is rarely mentioned. However, as far as Thomas Malthus, the original economic doomster, was concerned, the "passion between the sexes" was central to economic malaise.

If Malthus were alive today, he would no doubt argue that the Western economy is paying the price of excessive population growth in the world's poorest economies. An increase in global labor supply exerts downward pressure on the wages of Western working classes, those with whom the world's poorest compete for jobs, raising inequality and encouraging businesses to pursue cheap labor. The result is a reduced incentive to invest and slower global growth.

Malthus' emphasis on population growth has long been brushed to one side. That's because for much of the 19th and 20th centuries, his prediction of economic stagnation did not ring true — at least in the West. Not long after he published his "Essay on the Principles of Population" in 1798, Europe and North America entered a period of sustained economic growth. The work of the male inventors of the Victorian age was key to this growth, but it wasn't the only factor. There was something Malthus didn't bet on: the empowerment of women.