Most families have stories, favorite tales about near-calamities that happened when an energetic child slipped off the parental radar for a few minutes: That Time Bubba Fell Out of the Fishing Boat, or The Day Mom Lost Me at the Mall.

Mine dates from an incident I was too young to recall, but which has been retold over the years. A distracted baby sitter didn't notice when I wandered over to a neighbor's driveway, where a resident backed his car out of the garage and over my 2-year-old self.

Since this was the era when cars were as wide as a barn door, the tires passed on either side with plenty of clearance. The damage came to a few scrapes and a bump on the noodle from being knocked down.

But I loved hearing the tale of my parents' panic on being summoned hastily from their undergraduate classes at the University of Texas, and their profound relief on finding me in the emergency room chortling merrily with a doting nurse. With every retelling, I basked in the warm security of knowing what a scare they'd gotten.

How many of those happen every day? About a million? There was one last week, recounted in the Racine, Wis., paper about a local family wobbly with relief after their 16-month-old daughter was revived from a near-drowning.

Relatives found the toddler floating, face down and motionless, in a backyard kiddie pool after she slipped away from a family party.

Somebody quickly summoned a neighbor, an off-duty police officer, who performed chest compressions until the baby suddenly started gasping and crying and puking water.

The tidy article from the Racine Journal Times had a happy ending and a serious message.

"Never put in your mind that your kids can't get something past you, because they can," said Heather Walters, who said she turned her back on Ava for just a couple of minutes as dinner preparations were being made.

That story was published about the same time Catherine Stocco of Coppell was pronounced dead.

Catherine was about the same age as little Ava Walters. The circumstances weren't much different — Catherine and her 3-year-old brother, Marcus, were healthy, well-cared-for children watched by a loving adult who happened to look away for a couple of minutes.

Like the Walters family, the Stocco children's father acted fast, diving into the backyard pool to pull the children out, performing CPR, summoning help. But his children died.

What was the difference between these two cases? Two minutes, three? The cop next door? Luck?

What was the difference between me, all those years ago, toddling off to a neighbor's driveway, and Marvin Segovia, a Garland toddler who died a few weeks back? Marvin slipped away from his dad and wandered into the driveway, where he was run over by his mother, who didn't see him in the dark.

Not much difference, except that my family has a funny story to tell, and the Segovias will probably never recover. Not much difference, except the Racine Journal Times story is about grateful, relieved parents. Imagine the hell of grief and self-reproach the Stoccos of Coppell must be enduring.

No one lesson in all this, except that most families are lucky and very few aren't. That, and a reminder of something everybody knows but occasionally fails to keep front-and-center. "Never put in your mind that your kids can't get something past you," the lady in Wisconsin said. Never assume they can't slip outside, can't work the latch on the door, can't get out of their car seats or find the handgun in the bedside table.

"Because they can."