If you've ever been a tad bit curious why farmers often have large families, there are studies that point to several different reasons.  In addition to the fact that the farming profession provides more flexible opportunities for a husband and wife to “grow the family” than most other professions,  there are both practical and fundamental worldview explanations that shed additional light on this historic trend.

Referenced Resources - 

“People working in this profession have the most sex”
https://www.foxbusiness.com/markets/people-working-in-this-profession-have-the-most-sex