Assortive Mating's Contribution to Income Inequality

For a long time, I've suspected that "assortive mating"--marrying someone from a similar socioeconomic background, educational institution and/or vocation--was an important contributor to income inequality. Far from the only one, and the factors are probably multiplicative, such that if the other factors were diminished, the contribution of assortive mating would be proportionately diminished. But nevertheless significant and worth considering.

This article makes the point, and claims statistically that something like 25% of income inequality may be explained by the contribution of assortive mating.