I was seven years old when I realized that very young babies were being flung into the local swimming pool. This was quickly followed by the shock that my own baby sister—freshly pink and implacable—was one of those being tossed. Of course, all this was done under the fretful gaze of my mother, who, like the other mothers, would stand in the waist-deep water while the fathers stooped at poolside and gently dropped their infant children. After the hush there would be a grand, syncopated splash and then the mad scramble of baby retrieval in the foam.

My girlfriends and I, shapeless bodies hidden under our bikinis, watched this in silence from the springboards at the other end of the pool, stupefied. We had grown up with the conviction—burned into our consciousness by our parents—that water, although great fun, presented countless enticements to death. And so we lived with ironclad parental injunctions, veritable commandments of swimming: the thirty-minute post-lunch wait, the no-spitting-water rule, the zero-tolerance policy on horseplay. We had water wings and flutter boards clamped to us and were subjected to swimming lessons so unremitting and arduous that they should have alerted child welfare authorities. When-ever fatigue or faltering technique caused us to begin to sink, our swim coaches would exhort us with the universal command intended to forestall drowning: kick, they screamed. We kicked a lot. So the change in our parents’ attitudes—almost more than the act of throwing babies into the pool—caught us completely by surprise; we stood gape-mouthed. Anything was possible.

Soon after that I remember seeing this sort of activity shown repeatedly on television. Footage from underwater cameras captured the crystalline splash of countless babies like my sister. The infants were always shown paddling through clear blue water, looking infinitely pleased and confident, like astronauts on a spacewalk. This was the new way to learn to swim. Humans were natural swimmers, it was argued; lessons and graphic warnings only generated unnecessary fear, estranging us from our natural, amphibian tendencies. And so the flinging began.

My mother now downplays her participation in the baby-flinging method of swim training that gripped the nation in those days, although when it’s mentioned, like now when I bring it up in the spirit of communal nostalgia while sitting at my kitchen table, she defends the action, or, more precisely, the motivation behind it.

“It made your sister a great swimmer,” she says.

Janet lifts her head enough that we can all register the basset-hound arch of her eyebrow.

“Well, you are,” Mom continues, always retaining the right to be offended by the incredulity of her daughters.

My mother gets up to clear away the emptied teacups and the plate with two remaining shortbread cookies, clearly performing the act with more vigour than is necessary. An undisguised clattering in the sink, the audible snap of a dishtowel.

“You had to bring it up,” Janet drones, not looking up from the curling pieces of paper in front of her.

I close my eyes. From outside my kitchen window the reports of crickets rise, almost drowned out by the adenoidal hiss of the baby monitor. The cupboard door claps closed in punctuation. A breeze sifts through the rooms on the first floor, gently eddying doors on their hinges. I imagine the air pouring upstairs like an ocean current, brushing my sleeping son’s hand, rippling under the crib that holds my daughter. Tonight the whole house feels like a giant animal taking short skimming breaths. My sister shifts to get comfortable under her growing stomach. She exhales after this manoeuvre, the effort almost sufficient to create a sigh. My mother, hurt feelings forgotten, returns to the table. When I open my eyes they’re sitting there just as I’ve imagined, which shocks and delights me.

My sister stares intently at the picture in front of her, disengaging only to shuffle the papers and view the next. A pointillist image in black and white, clusters that form a line or a swirl that from a distance could represent the gathering winds of a hurricane. But on the paper that has her name on the corner she swears that she can make out the curve of a human forehead, tracing it with her forefinger. In another, a heart is caught between its hummingbird beats. My favourite is one where out of complete visual chaos a perfect gloved hand of delicate bone emerges, as though pressed up against a pane of glass.

“They don’t tell you the sex anymore, do they?” I say.

“Lawsuits,” Janet replies. “People paint the baby’s room pink, buy dresses and choose girls’ names, all based on the ultrasound, and whoops.”

“Still, that’s a lovely surprise,” my mother says, “a little penis.” She pauses after saying “penis,” as though luxuriating in the reticent thrill. Grand-children have made it safe for her to say the word in company.

When I was pregnant with my first, I was as excited and curious as any mother-to-be, but those books designed to tell you what to expect during pregnancy seemed vague or focused on issues like properly decorating the baby’s room. So instead, I bought an embryology textbook from the university bookstore and read about what was happening inside me. The diagrams showed how the cells moved in an orderly way to form a plate that pinched and folded into a tube. In this way a brain was assembled, its surface corrugating, connections made that would eventually be another universe. Within weeks the shrimp-shaped mass had budded limbs and taken on a human form, cells streaming in every direction, bringing a body into existence. It was as though I could hear the activity humming inside me. Janet’s husband Bob, who’s an anesthesiologist, found me reading the book once and hovered silently over my shoulder. He said nothing but I knew what he was thinking. He was right, I suppose; it did keep me awake nights, thinking about the hum, the complexity of the whole thing, the journeys that had to be completed. All those contingencies. When my son was born, fantastically normal, I put the book away. For my second it stayed on the shelf.

The monitor crackles down the stirrings of my daughter in her room. We look at each other, all of us silent for a moment, waiting for her voice to call out for me, but nothing comes. Janet has finished studying the last of her ultrasound pictures, which shows the clearest image of her unborn child floating in a sea of deep, amniotic black. She’s happy, of course, but she also has that other look, an extra furrow that I’ve worn and that I’m certain my mother knows as well. For anyone looking in at us through the window of this suburban house I suppose we three must appear to be the picture of contentedness, even self-satisfaction. But my sister’s face shows more than that. She hears the hum. Yes, it’s different here at the table, more complicated. I just sit beside her, thinking of what I can say to help, but no words seem to do. Besides, in a moment a kick will come without anyone’s urging.