The presence of a large number of full siblings who reached reproductive age in ancient times suggests several things about family sizes and fertility rates during that period:
High fertility rates: The fact that many full siblings reached reproductive age indicates that families in ancient times likely had high fertility rates. In the absence of modern birth control methods, and in societies where having many children was valued for various reasons (such as labor for agricultural societies or ensuring survival and continuation of the family lineage), families tended to be larger.
High infant and child mortality: While many full siblings reached reproductive age, it is also likely that there were significant infant and child mortality rates in ancient times. Many children might not have survived past infancy or early childhood due to factors like disease, malnutrition, or lack of medical care.
Importance of reproduction: Reproduction and the ability to produce offspring were highly valued in ancient societies. It was often seen as essential for the family's prosperity, continuation of the lineage, and support in old age.
Limited birth control methods: Ancient societies lacked modern contraceptive methods, which could contribute to higher fertility rates. While some cultures might have used herbal remedies or other traditional practices to control fertility, they were often less effective than modern contraceptive options.
Higher family sizes: With a combination of high fertility rates and significant infant and child mortality, it is likely that families in ancient times tended to be larger than what we see in many modern societies today.
Economic and societal factors: Family sizes and fertility rates in ancient times were also influenced by economic factors and societal norms. For example, in agrarian societies, larger families might have been beneficial for agricultural labor, while in more urban societies, smaller families might have been preferred due to economic constraints or social considerations.
It's important to note that the specific fertility rates and family sizes would have varied across different ancient civilizations, regions, and time periods. The data we have about ancient demographics is often limited and comes from a variety of sources such as historical records, archaeological evidence, and demographic models, so our understanding of ancient family sizes and fertility rates is not as precise as it is for more recent times.
In summary, the presence of a large number of full siblings who reached reproductive age in ancient times suggests that high fertility rates and larger family sizes were common, while also implying the challenges of infant and child mortality in those societies.