Children living with a single parent or a step-parent are just as happy as those living with two biological parents, according to a recent study.

Researchers from the NatCen Social Research found that whether children lived two biological parents, a step-parent and biological parent, or in a single parent family, made no difference to how happy they were.

"We found that the family type had no significant effect on the happiness of the 7-year-olds or the [11-15-year olds,]" Jenny Chanfreau, senior researcher at NatCen, said in a statement. "It's the quality of the relationships in the home that matters -- not the family composition. Getting on well with siblings, having fun with the family at weekends, and having a parent who reported rarely or never shouting when the child was naughty, were all linked with a higher likelihood of being happy all the time among 7-year olds."

For the study, researchers analyzed data from the Millennium Cohort Study on 12,877 children aged seven in 2008. They found that their home situation made no difference on how they rated their happiness.

Sixty-four percent of children who lived with two biological (or adoptive) parents said they were happy "sometimes or never," and 36 percent said they were "happy all the time." The exact same percentages were found door those living with one-step-parent and one biological parent, and for those living with a lone parent.

Even after researchers statistically removed the effects of other factors such as parental social class so that the effects of family type were isolated, the results showed no significant differences.

Researchers found a similar result when analyzing another set of survey data from 2,679 children aged 11 to 15.

Chanfreau said that instead, factors such as relationships with others were found to be both important and statistically valid, including getting on with their siblings, having friends, having fun with the family or not being bullied at school.

"Pupil relations at school are also important -- being bullied at school or being 'horrible' to others was strongly associated with lower happiness in the seven-year-olds, for instance," Chanfreau said in a statement.

The findings were recently presented at the British Sociological Association's annual conference in Leeds.