is when a woman gives birth to a baby

Antinatalist, eh? You'd like this video on Arthur Schopenhauer by School of Life.

No, I mean on a much deeper level.
Like Schroedinger's cat taken to the nth degree.
The effects on the planet are not computable by our current mathematics.

Imagine if Hitler wasn't born. (I know this isn't an accurate example, but it explains to most people) What the world might be like. The huge web of connection, of cause and effect spreading out from that single life.

Now, imagine that time literately changes when you add another piece to the puzzle. The entire framework of life on this planet is changed by one child being born. For each and every child. When each one is born, it multiplies the number of future possibilities. Nothing the person does during the rest of their life is as world changing as that.