According to a new research, couples who want to stay together should get married before having their first child.

It further revealed that three-quarters of couples who tied the knot before having their first baby were still together 15 years later. However, less than half of those who had a child before marriage kept their union intact.

The research, which was carried out for the Marriage Foundation think-tank, revealed that marrying before starting a family was a major factor in keeping parents together.

In addition, the age of a couple when they became parents was also found to have no impact.

According to the foundation's research chief, Harry Benson, the findings indicated marriage is a bigger influence on parents having a solid relationship than education, which is often cited with wealth as a key driver in encouraging couples to marry and stay married.

The study was based on 1,783 mothers with teenage children who took part in the state-financed survey called Understanding Society.

It found that 76 per cent of mothers who married before becoming a parent were still with the father when the child was 14 or 15 years old.

By contrast, of those who married after the birth of their first baby, only 44 per cent were still with their husband when their first-born reached the age of 14 or 15.

However, more than eight out of ten women with a degree were still married as their child approached 15, so also were 74 per cent of women without.

The report said the age of couples 'had no effect whatsoever' on their chances of staying together. Benson said: "This shows that education and age do not dictate the success of relationships as was previously thought.

"It barely seems to matter if women are younger or older, degree-educated or not; so long as they make a plan for their future and marry before starting a family, they have a really good chance of making that relationship last.

"It stands to reason that there is one system that works best. It is one that worked for years. While it is right that we have done away with the social shame of having children outside marriage, we should not lose confidence in the value of crystallising commitment before starting a family.

"The message of this research is clear. For any couple thinking of having children, their best chance of staying together in the long run is by getting married first."

Among the couples still together 15 years after the birth of their first child, 92 per cent were married. With cohabitee mothers who never married, less than a third were still in their relationship with the father 14 or 15 years later.

Sir Paul Coleridge, the former High Court judge who heads the Marriage Foundation, said: "The next government has a real chance to reduce the marriage gap between the haves and the have-nots.

"There is a serious and growing cause of real social inequality. The myths and misperceptions, such as that cohabitation is as stable as marriage, should be eradicated by clear public statements and education.

"Governments cannot legislate directly for stronger families but they can foster the right environment and so make a real difference."