是说家长们更高兴。孩子们是总有朋友，但没说他们更高兴。

有个评论比较有意思：

“So many of these studies are just identifying correlation rather than causation. You have to look at the type of people with greater probability of having 4 kids. Most of them are conservatives that have financial resources. Liberals are more likely to have an only child or no children and just about every peer reviewed study indicates that liberals by nature are less happy people because they always see the flaws and victims in society.”