The Duke and Duchess of Cambridge have three. The Duke and Duchess of Sussex have one on the way. Ordinarily, the British settle for two (as do Kiwis). So how many children makes for the happiest families?
Here's what the research tells us:
In 2011, the British parenting website bounty.com carried out a major survey to identify the factors that make for happy families. They asked 2116 parents to rate their children's behaviour on a number of dimensions – for example, "ease of care" and whether they "generally like each other".
![The arrival of Prince Louis made the Cambridges a three-child family. Photo / Getty Images](https://www.nzherald.co.nz/resizer/v2/72ZZXWXNPGNGM36GJURATJAFRI.jpg?auth=ebc99d39f26fd30161863b62d73161859501667ddb6cba98513372cc2c7fc63f&width=16&height=11&quality=70&smart=true)
From this data, they drew up a list of the happiest families according to numbers of children. A family with two girls came top, followed by those with one boy and one girl, then families with two boys. Three-child families were rated less happy, and four-child families less happy still – except for families with four boys, which ranked sixth on the list of 12.