Earlier quoted context omitted.
I would assume that they mean your great great grandparents benefited greatly by having kids because it brought in more labor while it mostly just cost food. These days there are tons of extra costs to having kids that didn't exist in the past and none of those costs are offset by their labors.
We’re reaching further into the past than great great grandparents to get to the large families for farming but sure. Calling it a “fine” to have kids is really bizarre framing though.
The USA didn't change things up considerably until the 1930s: https://en.wikipedia.org/wiki/Child_labor_in_the_United_Stat...
Not soon after, obviously ww2 and then the baby boom after that. The role of children in families changed hugely in the 20th century.