I read The Selfish Gene by Richard Dawkins when I was in high school and it greatly shaped my understanding of the world and people in general. The key takeaway for me is that humans (just like every other living being) are just gene propagation machines.

We want to believe we are special (as individuals or as a species) but we're not. We are machinery that is purpose built (by evolution) to reproduce our genes. Nothing more, nothing less.

One thing I took away from this understanding is that while many people want to assign some mystical/special reasoning for why one should have kids, it is quite literally the most basic thing one could do. Practically every living being that has ever lived has reproduced as it is our sole evolutionary function.

People want meaning in a world that offers none. We are gene reproduction machines hurtling through space on a rock and inconsequential characters in the billion+ year story of the universe.

You can be depressed by that information or let it bring you immense joy every morning when you wake up and realize how lucky you are to participate in this journey for a tiny fraction of time with no purpose but to enjoy your little part.