diy_fun_uk comment was based in the current time, as were other similar claims.
There is no indication that having several children is a current strategy of gaining extra income.
In many countries there is no such thing as child benefit, but there are still large families. So what's going on there?
According to the popular belief, countries that have high cild benefit payments should have high birth rates.
But that isn't the case.
Norway's birth rate is 1.55
UK's birth rate is 1.56
But Norway pays way, way more in child benefits, with a population of just 5,000,000 people.
Large families looks much of a cultural thing.
The comment stands as an indication that this has gone on for longer than you think.
Birth rates are falling across the world. Why?