As I sat down with my son for the birds-and-bees talk, it struck me how natural and straightforward conversations about human reproduction can seem compared to the more complex theological discussions that arise when examining biblical accounts.

After a very successful discussion, my son and I reviewed Genesis 1:28, where God commands Adam and Eve to “be fruitful and multiply, and fill the earth.” This passage, so simple in its directive, underscores a profound mystery: How did humanity grow and develop after the creation of our first parents, particularly in light of traditional Christian teachings?

This question is not merely academic. It touches on foundational aspects of Christian doctrine, particularly when viewed through the lens of the Catholic understanding of original sin, divine creation and biblical interpretation. 

“The Bible mentions that Adam and Eve had three sons,” said my son. “So how did they marry or have children?”

Great question, kid!

Genesis provides a clear command for human procreation, but the specifics of how this unfolded after Adam and Eve are less explicit. According to Catholic teaching, Adam and Eve were the first humans created by God. The Council of Trent (1545-1563) affirmed the doctrine of original sin, teaching that Adam and Eve’s disobedience introduced sin into the human condition, affecting all their descendants. This foundational belief reinforces the idea that humanity's fall was a real, historical event with profound implications for all people.

Indeed, among the five decrees on Original Sin promulgated by the Council of Trent is that Adam’s sin is transmitted to all mankind through propagation. Accordingly, we cannot contravene the teaching on Original Sin by making exceptions to the fact that all humans are descendants of Adam and Eve. Some Christian teachers (non-Catholic of course) wish to introduce an explanation that there may have been other humans created by God for the children of Adam to marry. This simply rejects the true impact of Original Sin.

Back to the children of the first couple. Genesis 4:1-2 introduces us to Cain and Abel, the first sons of Adam and Eve. The narrative briefly mentions their births but does not elaborate on the process by which humanity multiplied. Genesis 5:4 adds that Adam “had other sons and daughters,” but details about these other children are notably sparse.

Genesis provides minimal details about Adam and Eve’s other children, suggesting its focus is more theological than demographic. The Catechism of the Catholic Church reinforces the view that God’s creation was initially perfect and that Adam and Eve’s actions introduced sin into the world, leading to their exile from paradise.

The Catholic Church teaches that divine law was revealed to mankind gradually. Regarding human relationships and social order, the Catechism emphasizes that marriage is an important social institution and a crucial religious one, establishing rights and duties between spouses and toward their children (CCC 1631). As humanity grew in its understanding of God’s moral law, these principles became more clearly defined.

As I reflected on the conversation with my son, I realized that the complexity of family narratives in Scripture mirrors the challenges of teaching and understanding the Catholic Faith. The simplicity of Genesis 1:28 — and the rest of the early biblical account — contrasts with the depth of its implications, reminding us that faith involves navigating both clear teachings and deeper theological mysteries.

In discussing these topics with younger generations, it’s important to balance clarity with sensitivity to the historical and doctrinal contexts of these biblical accounts. I never asked these sorts of questions as a child, but my budding theologians are clearly onto something. This is one of the many reasons I’m incredibly happy to be a Catholic: we are never without guidance, instruction and answers to tough questions.