The trend has profound implications for social inequality, experts warn.This preference to "marry within the group" is strongest at the top and bottom of the education ladder.Those with no educational attainment are over 80 times as likely to partner with each other compared to the average, while those with doctoral degrees are nearly 15 times as likely to marry each other compared to the average Over the same period, the percentage of people (aged 15 and older) with a university qualification doubled.In a paper examining six decades of marriage between different education groups in the US , Schwarz and her colleague Robert Mare found college graduates were increasingly likely to intermarry, while those with the least education were increasingly unlikely to marry up.These trends "are consistent with a growing social divide" along educational lines, they wrote.Going one step further, a Danish study from Aarhus University's Gustaf Bruze found that about half of the expected financial gain from higher education came from the chance to marry a high-earning spouse, rather than improved job prospects.When marriages between different education levels within the same sector are included among "mixed marriages" (eg master's and bachelor's degrees), the ABC's analysis shows more Australians are crossing the education divide for love compared to 20 years ago.About 36 per cent of partnered Australians are married to someone with the same level of education, down from 42 per cent two decades ago