Young people without educational qualifications are increasingly being left on the shelf by potential partners, New Zealand researchers say.
Social researchers Paul Callister and Robert Didham have found that the so-called "decline of marriage", matched by a growing tendency to stay single, is largely confined to the uneducated.
Young adults of "marriageable age" (25 to 34) are just as likely to have a partner today as they were 28 years ago - in fact slightly more so if they are women.
But for young men of the same age with no qualifications, the chances of having a partner have dropped by a fifth, from 65 per cent to 52 per cent.
For young women with no qualifications, the chances of a partner have plunged by almost a third, from 72 per cent to 50 per cent.
"The well-educated haven't gone away from those ideals at all, in fact maybe they are going more back to them," said Dr Callister.
"But the trouble is that the disadvantaged [are no longer marrying] for whatever reason, whether it's better to be on their own because of benefits, or maybe they are even just lying, or they may have different relationships to what we imagine, for example they may be just thinking, 'He comes and goes'."
The paper, co-written by Statistics NZ demographer Dr Robert Didham, draws on Census data from 1986 to 2013.
Overall, partnering rates dropped sharply when unemployment skyrocketed in the 1980s. Men aged 30 to 34 with partners plunged from 84 per cent in 1981 to 70 per cent in 1991, and it was still 70 per cent in 2013. Partnered women of the same age fell from 85 per cent to 73 per cent in 1991 and 71 per cent today.
"There was a big restructuring. That created a one-off shock which changed partnering, the labour market and all those sorts of things," Dr Callister said. "Really it's like you had that one-off hit and it settles back and then you have cycles but it doesn't really change."
The main casualties of the employment "hit" were relatively uneducated men. In contrast, women over the past 30 years have moved dramatically into higher education and into paid work.
Only 7 per cent of women and 11 per cent of men aged 25 to 34 had degrees in 1986. By 2013 it was 38 per cent of women, now well ahead of 28 per cent of men.
As a result, couples aged 25-34 where both partners have degrees have increased from 4 per cent in 1986 to 23 per cent - in most cases with both partners in paid work.
Dr Callister said this "assortative mating" where people tended to marry partners with similar qualifications, combined with increased female qualifications and employment, had contributed to rising inequality.
"In the past maybe the lawyer would have married his secretary and she would have left the labour market. Now the male lawyer will marry a female lawyer, so they have that potential of increasing their joint income," he said.
A medical anthropologist and president of the Celebrants' Association, Dr Elizabeth Bennett, said the trends had implications for child poverty at the other end of the scale because those without qualifications were increasingly unlikely to have partners.
"The implications for child poverty in sole-parent families would, I think, be directly linked with this data," she said.
"They do highlight that more analysis is needed."
Couple clicked with a meeting of their minds
Jemma Field says her husband Jamie Nelson was the first "intellectual match" she had dated.
Ms Field, 32, will submit a doctoral thesis in art history at Auckland University next month. She and her husband, also 32, met when they found themselves both commenting on Facebook photos posted by a mutual friend who lived in London.
It took them two months to start dating in person. They moved in together nine months later and married three years after meeting.
Mr Nelson doesn't have a formal degree but has been a serial entrepreneur in information technology businesses since he left school, largely in creative industries, which gave him an insight into Ms Field's doctoral research into patronage and identity politics in 17th century England focusing on Anne of Denmark, the wife of King James I.
"He has a very good understanding - at the time I thought stronger than mine - of how one expresses identity through physical and cultural means, so even at the beginning I was quite taken with his intellect. He's the first intellectual match that I've actually dated," Ms Field said.
"You need someone as a partner who supports you emotionally, spiritually, intellectually.
"I used to think that intellect was not my top priority, but actually it's really important to me because it forms such a large part of my everyday life and for who I am as a person."
The couple decided to get married, even though neither of them is religious, because they wanted their friends and families to support their relationship.
"I think you have a responsibility to look after your own relationship and that your friends and your relatives have a responsibility to help facilitate it if needed," Ms Field said.
They married in an art gallery with Ms Field's best friend as their celebrant.