Let me explain: There's an old philosophical story about how experience differs from knowledge. It's about a color researcher who happens to be color blind. She has studied wavelengths and spectra and knows all about the color red, but has never truly seen it. She may even be considered the world's expert on knowledge about the color red. She knows how the brain fires when it sees red and has read about how it's a different color from green. But does she truly know what "red" is?
Then one day she gets gene therapy and receives properly working opsins in her retina which allow her to see the color red. She turns to a red Rothko painting (hey, this is my story, I can tell it how I like) and sees a brilliant wash of crimson for the first time. She has gained something from the operation. But what is it exactly that she has gained? Not knowledge but a new experience. She sees red for the first time. This subjective experience is what philosophers call qualia.
Now comes along an argument from a philosopher that puts this into a new context. According to this argument, before you have a baby, you know all about it (including your own experience of being a baby). Maybe you can even test its DNA to find out about the baby. But you have never experienced being a parent. When you hold that baby for the first time, you're like the color researcher seeing red for the first time. This is a totally new, subjective experience, and this is so uniquely valuable that (philosophically speaking) it outweighs all the inconveniences and stress that result from that tiny squalling mass. The baby is a new color, a color no one in the world has even seen before, and (for the biological parents) a color literally mixed from the two parents' colors.
All this and more is summarized in the Percolator blog post "Maybe You Should Have a Baby". Including this quote:
Moreover, since having one’s own child is unlike any other human experience, before she has had the experience of seeing and touching her newborn child, not only does she not know what it is like to have a child, she cannot know. Without having the experience itself, she cannot even have an approximate idea as to what it is like to have that experience. Like the experience of seeing color for the first time, the experience of having a child is not projectable. All of this results from the fact that having one’s own child is transformative—and far more so than the experience of seeing color for the first time.
I would only add that, being the parent of four boys, I can attest that each of their "colors" is a brand-new gift to the world, unlike the others yet equally beautiful. One of the joys of parenting is finding out just how different your children are from eachother, and from you. It's also one of the greatest difficulties. Yet each child is indeed a work of art, and I'm grateful for each one.