Children pay the price when divorce is made easier, according to a major study.
The inquiry, which examined families in 13 countries, found that the children were less likely to succeed in life.
Those reaching adulthood in the 1970s were far less likely to go into higher education than their counterparts in the 1940s and 50s, when divorce laws were much more restrictive. The easy divorce effect was so strong that children whose parents broke up in the liberal 1970s were nearly five times less likely to go to university than those whose parents parted in earlier decades.
Researchers suspect children of the earlier age group found it a relief when their parents parted after conflict and recrimination.
But they said many couples in the other age group who broke up in the 1970s were in relatively harmonious marriages that ended thanks to the growing ease of divorce.
Divorce without conflict causes deep shock and lifelong damage to children who had no reason to suspect their home was about to break up, the researchers concluded.
The findings are a major blow to the assumptions held by advocates of no-fault divorces. Campaigners for divorce reforms routinely maintain that making divorce easier, simpler and cheaper would be good for children whose parents want to leave their marriage. The study was carried out by a team led by Professor Martin Kreidl of Masaryk University in the Czech Republic.
It covered the history of more than 93 000 people recorded by UN-based surveys since the 1940s, and followed family break-ups in Australia, Belgium, Bulgaria, the Czech Republic, Estonia, France, Germany, Hungary, Italy, Lithuania, the Netherlands, Norway and Romania.
It said: "The burden of parental break-up became much stronger between 1940 and 1979.
"The burden associated with parental separation clearly becomes more negative when divorce is more common. The growth of the negative effect is rather strong."
Researchers said a child whose parents divorced in the 1940s or 1950s was two percent less likely to graduate from a university than other children. By the late 1970s children of broken homes were nearly 10 percent less likely to go through university.
The study, which took into account the importance of factors such as the educational level of the divorcing couples, said the impact of divorce was most severe for the children of the least well-off.
It added: "The dissolution of a high-conflict family may be a relief for the child, as well as for the parents. The break-up of a low-conflict family, on the other hand, is more likely to harm the child.
"The negative effect of parental separation on children’s odds of graduating from university increases over birth cohorts and is stronger when separation is more common.
"This finding can be attributed to the declining levels of conflict accompanying separation and to the changing composition of the population of dissolving families."
Laura Perrins, co-editor of the Conservative Woman website, said: "This research shows yet again that divorce damages children, especially those from low conflict marriage.
"It would be very wrong to make divorce easier."