“How??? You are almost 40!” exclaimed my mother, when she saw me packing up some of my son’s paraphernalia — his baby carrier, car seat, and other odds and ends of infanthood – for storage.

Gee, thanks, Mom. (I guess I look 40 now, but I am not yet. And what was with the “how?” Plenty of my friends have had kids at 40. I digress.)

She had guessed correctly: I was packing it all away for a second one. I suspect she was surprised to learn I might be planning on having a second child, when I took so much time over the first.

I didn’t know what to say; there was no plan, not really. This was a prudent “just in case” kind of spring cleaning.

Because having a second child is tempting, in theory. Everything is supposed to be a breeze with Thing 2. You are a pro, less confused and less fussed about the hundred things you worried about with the first.  The second child costs less (because of the saved stuff!), and you are wiser about buying things you only actually need. Even the delivery is effortless, I am told. “She just slipped out!”

At least, that is the story you hear — until you see what it looks like in real life.

I recently ran into an old friend after many years. In our brief and rushed conversation (as her 4-year-old tugged at her and her infant clung to her), she mentioned she had finally returned to work after having her second child and was struggling to hold her head above water. I nodded with sympathy; I was flailing with the one.

My husband, though, was less understanding.

“What is the point of complaining? She made a choice to have the second one,” he said after we parted.

Leaving aside the possibility that it must be harder on her than her spouse because she must be bearing more of the child-rearing burden than he, a part of me did agree with my husband.

Parenting a child is hard hard work. However much our hearts are filled with love for our children, it is a fact that our lives and our lifestyle are shot to shit after they come along. We are more stressed and exhausted, more frequently at the end of our tether. It is non-stop, relentless and takes every last drop of patience out of us.

I haven’t had a restful night of sleep for three years (including the year I was pregnant). My last trip with my son has left me fearful of travelling with him ever again after he howled for the entire 2.5-hour flight. Many of these things will probably get better (the tunnel, though, is looking endless right now), but why would I want to go through this all again after having a second child?

Back in the day, before my own child, I could see the lure of a full house, particularly as an only child myself: a noisy, messy, boisterous, happy house where there is always something going on, never boring.  Sure, there would be a fight for space, for a breather. But I’d had plenty of alone time growing up, and the grass was greener on the other side.

There was something more, too — a beckoning sense of belonging. Your brothers and sisters were your peers that you belonged with. They would grow old with you, and you would always be bound to them, even after you move apart. There is something very comforting about that. Maybe kinship is just one more comfort we want to give our children.

But I grew up happy and loved as an only child. I had my parents’ undivided attention, plenty of toys to play with, and a lot of space to spread them out in. My parents, for their part, were more relaxed, more able to pursue their vocations and interests, and share both with me. And when I remember my childhood, I think I would be all right sticking to the one. Because I know he will be all right. We all will.

Regardless of what we ultimately decide and why, having a second child is a choice (assuming no accidents), and choices have consequences. Choosing a fuller house means something has to give — maybe our peace of mind for a bit, our careers for a while, the dream of a clean house in which we can entertain guests with lovely crockery.

And choosing just the one means a pang when we notice his loneliness, when we realize he has fewer people to call his own.

I think that is what my friend was trying to say that day. She wasn’t complaining; she was just explaining the consequences of her choice.

I have time (despite my mother’s conviction to the contrary) to weigh the options. Until then, the baby stuff is packed and kept away in neatly labelled boxes to make it easy to find, just in case.

Because sometimes, that is what is needed — clearing out the old stuff to make space for the new, in your head as well as in your house.