PARENTS who row constantly and are in an unhappy relationship will sometimes stick together for the sake of the kids.

However, new research suggests that parents who stay together to avoid upsetting their children may not always be doing the right thing.

A study of nearly 7,000 10 to 15-year-olds by the Children's Society found the difference between a young person's family getting along – or not – explains 20 per cent of the variation in happiness with life.

Differences in family structure, such as parents living apart, only accounted for two per cent of the variation in happiness.

Penny Nicholls, the Children's Society's director of children and young people, says in the society's Good Childhood Inquiry report , it was clear one of the most important things for children was the relationship with their families.

She says: "It comes as no surprise the biggest impact on children's well-being is conflict in families.

"What may take others by surprise is that different family forms had a very limited impact on overall well-being."

She says the society found children are able to thrive, almost regardless of what form their family takes.

She says: "The most important factor is the quality of the relationships.

"This sends out a strong message to parents, it's not just about the quality of the relationship between the child and the parent, but also between the parents themselves, and how that impacts on children in the way they feel about themselves."

She says the thinking that a happy family is one where both parents live together is rooted in history.

She adds: "The family has changed over the last 50 years, and there's been an acceptance of different family forms, but what people hold in their heads is an ideal situation where families always stay together."

A significant upheaval in a child's life – a separation or a new member coming into the family – does have an impact on a child's well-being, but they recover quickly and a key factor in that recovery is the quality of their parents' relationship.

The survey also found a child's appearance and confidence affected their happiness, with 17.5 per cent saying they were unhappy with how they looked, and 16 per cent saying they were unhappy with their confidence.

Almost twice as many girls, 21 per cent, were unhappy with their appearance as boys, 12 per cent.