The notion of "making a good match," a staple of the writings of Jane Austen and Henry James, continues in contemporary romance novels. At the same time, income inequality commands increasing attention from economists. Lately we've been learning just how much these two topics are tied together.

These days, an investment banker may marry another investment banker rather than a high school sweetheart, or a lawyer will marry another lawyer, or a prestigious client, rather than a secretary. Whether measured in terms of income or education, there are more so-called power couples today than in the past, one manifestation of a phenomenon known as assortative mating, or more generally the pairing of like with like.

The epitome of a modern power couple: international lawyer Amal Alamuddin and her actor husband George Clooney. Credit:Getty Images

These matches are great for those individuals who can build prosperous and happy family alliances, but they also propagate inequality across the generations. Of all the causes behind growing income inequality, in the longer run this development may prove one of the most significant and also one of the hardest to counter.

For instance, the achievement gap between children from rich and poor families is higher today than it was 25 years ago, according to a recent study from the Pew Research Centre. Furthermore, higher income and educational inequality increase the incentive to seek out a good marriage match, so the process may become self-reinforcing.