In a way, it was prescient, my blowing bubbles in the back yard and him darting across the grass, hopping to pop them, and then running toward another one. “Wow,” he repeated as I blew through the plastic wand and created bubbles the size of tennis balls that would float in the air like fireflies.

Little did he know his own bubble was about to burst.

For just shy of two years, he had been the center of the universe to the extent even his good old dog – not to mention everybody else – would roll over to please him.

That’s the way with firstborns. They have baby books in which every detail of their early existence is recorded in calligraphy and chronicled in dozens of photo albums. They have parties and presents and play groups. They have new sleepers and bumper pads, not hand-me-downs. They have grandparents who oogle and ahhgle over every movement – including the most basic.

Why, it’s no wonder they are the apple of our eyes: they’re the wonder. Then, suddenly, their little world is topsy-turvy. Someone puts a T-shirt over their head that proclaims, “I’m the Big Brother.”

Sure, there has been a second crib upstairs for a month or so, and a new bouncy seat was assembled. Tiny diapers were in the changing table above the toddler-size ones, and the infant car seat was brought out of storage.

But it didn’t make sense to him until a day when the whole household was spinning as if caught in a tornado.

It was one thing to pat the bassinet and say an imaginary “bebe.” It was clearly another to march into a hospital room with HIS daddy and find a tiny, whimpering, wiggling baby boy lying next to HIS mama.

So the transition began. And the scene reminded me of a New Yorker cartoon in which a small boy opened the front door and found his parents standing there, cradling an infant. “I hope you kept the box,” he said blankly.

Yet, there is no return policy for this particular present; and in time, the sandbox and the plastic pool, the toy trucks and alphabet books, the Animal Crackers and the good old dog will be shared.

At the moment, however, there is slight adjustment under way, something along the order of not always getting one’s way. Not ever again.

So, he thinks, as he gently kisses the baby’s cheek one minute and has an unprompted crying spell the next, this is what it means to be a sibling.

Oh, brother!