Researchers came to the conclusion after examining the lives of families with different combinations of children, both male and female.
The results show of all the variations, two girls make for the most harmonious family life as they are unlikely to fight, will play nicely and are generally a pleasure to be around.
It also emerged two girls rarely annoy their parents, make limited noise, often confide in their parents and are unlikely to wind each other up or ignore each other.
By contrast, doubling the number of daughters is likely to lead to a whole world of pain, the report found.
Full story: Want to be happy? Have two daughters