Single parents, do not worry as happiness levels of children does not depend on the number of parents they live with.
"We found that the family type had no significant effect on the happiness of the seven-year-olds or the 11-15 year olds," said Jenny Chanfreau, senior researcher at NatCen Social Research in Britain.
"It's the quality of the relationships in the home that matters - not the family composition," Chanfreau emphasised.
The study involved 12,877 British children aged seven in 2008.
Of those children living with two biological (or adoptive) parents, 64% said they were 'sometimes or never' happy and 36% said they were happy 'all the time'.
The exact same percentages were found for those living with one step-parent and one biological parent, and for those living with a lone parent.
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 the kids.
"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.