Happy couple lying on bed with babySleepless nights, endless nappies and the loss of a regular night out would, to some, sound like a recipe for stress.

But researchers say that bringing a child into your life really does make you happier... if you're married.

Scientists at Glasgow University based their findings on the experiences of tens of thousands of British parents and found that babies, far from driving couples over the edge, can strengthen the relationship.

Nearly 90,000 parents were questioned about their life and happiness and their answers revealed that the arrival of a tiny new person made marriages happier.

For serious joy, three children was the optimum, according to the Journal of Happiness Studies.

However, in stark contrast, those couples who were living together but had not tied the knot, found themselves discontented with their lot after the birth of a child.

Researcher Dr Luis Angeles told the Daily Mail: "The fact that people who live as a couple but are not married experience lower levels of life satisfaction with children is worthy of notice.

"It dispels the idea that the positive effect on married individuals is due uniquely to the fact that they can pool resources, such as money and time, to raise children.

"What separates married and unmarried couples is arguably not the possibility of pooling resources for the aim of raising children but the willingness to do so in the first place.

"As a rule, the arrival of a child tends to be seen as a blessing to a married couple and as a problem to an unmarried one or to a single mother."

Perhaps a shot-gun wedding isn't such a bad idea.