Historically, many societies have restricted women to the sole duty of birthing and raising children. In these communities, life—especially for women—was most valuable when people could produce offspring. As a result of this mentality, procreation is the primary purpose of life.
An example of such a society is British society in the Georgian era (1714 - 1830). Women had the sole duty of bearing children and raising them; everything else, including education and social life, was secondary. 
During childbirth, many prioritized the baby’s health over the mother’s. Consequently, many mothers died through infection, disease, or lack of proper care following childbirth. Since society considered procreation as the purpose of life, these women’s lives were considered to be fulfilled. 
In another example, women in Nigeria have a similar role in life. Women who are able to have children are considered to have fulfilled their life’s responsibilities. On the other hand, infertile women are considered possessed by witchcraft. Since society considers procreation as the purpose of life, infertile women would spend their lives trying to become fertile through divination or quelling the evil spirits. They would go through these efforts to be able to have children and give their live value and purpose. 
Georgian Britain and Nigerian society are just two examples of communities where life—especially for women—is most valuable when people could produce offspring. Procreation must be the purpose of life if producing children is held to the utmost importance.