Babies. it is a balmy day, and the beautiful weather brings them out in droves: Babies toddling on their chubby legs, infants sleeping in carriages with their rosebud mouths pursed around the dream of sweet breast milk. Along sidewalks, in parks, in the shopping mall, everywhere, babies are spreading their special glow.

Forty-five years old and the mother of two teenagers, I am well past the age of baby worship  -- yet the mere sight of an infant affects me so intensely that I temporarily lose control of both body and soul: I smile involuntarily, beg to pick her up and kiss her tummy, make silly faces regardless of who's watching. The scent of baby shampoo wafting up from the top of a soft skull  -- that's all it takes to bring me to the edge of ecstasy. And that is when I begin to ask myself: Where's my rocking chair? Do I still have that red-and-white quilted bumper for the crib?

My sons are 16 and 14. Afternoons, they play tennis and come home to flop on the sofa, greasy and sweaty, their hair matted beneath reversed baseball caps. They wear jeans big enough for Goliath and steal my Victoria's Secret catalog. Their rooms should be cordoned off with yellow crime-scene tape. This is where my original dose of baby lust has landed me.

That first wave hit when I was a newlywed of 26, though three miscarriages kept me from having a child until I was nearly 30. When Nicholas was born a short 20 months after Alexander, I indulged in a private fantasy: Me, standing at the helm of a large family  -- unlike the one I'd grown up in  -- expertly nurturing a clan of children while I juggled a successful career. Three children, maybe even four, seemed perfect.

But the ensuing years of family life proved more complicated than I had imagined. We postponed getting pregnant again for a variety of reasons: the demands of two children so close in age, my husband's travel schedule, my own work. As the years passed, we always told ourselves that next year would be a better time for another pregnancy, but the truth was that we couldn't manage more than was already in front of us. I couldn't imagine how we could stretch our arms around another child. Until now.

Why now? True, I have just celebrated another birthday. True, my sister recently had the baby girl I'd been dreaming about. But are my fears of aging or a persistent sibling rivalry explanation enough for this sudden seizure of the heart, this irrational desire for another infant of my own?

I would certainly make a much wiser  -- though perhaps less energetic  -- mother than I did when Alexander was born. It's not unreasonable to suppose that, with some luck and a soupcon of intervention, I might conceive again. Modern medical science has put humankind in an unprecedented position: For the first time we look not only to our bodies for the decision to reproduce, but to our hearts.

But none of these reasons to have another child gets to the root of my baby lust. No, the disturbing fact is that now that my children are teenagers, I have reached the end of one stage of my role as a mother. For the first time, the terrifying word "never" rises up in front of me. Will I never again hold an infant to nurse at my breast? Will I never shop with a daughter for a party dress, or a box of tampons, or a tube of lipstick?

I remember how I felt on the day I held Alexander in my arms for the first time: That drive to champion and to nurture, to bare my teeth against anything and anyone that crossed into his territory. The powerful feelings our children stir in our hearts are unique. They transform even the least passionate among us into fiercely protective and proud people. With the birth of our children we, too, are newly born. While having a baby may not grant us immortality, it surely does provide us one of the most absolute methods with which to deny the relentless drumbeat of each passing year, to find new wonder in the small details  -- from the falling autumn leaf to the raucous howls of the monkey house.

Still, when I ponder all the demands an infant inevitably makes, I know, ultimately, that I am not willing to relinquish the freedom that comes with packing away the baby equipment. But because banishing the dream makes me achingly sad, I rock the infants of friends; I buy dresses for my niece and let her play dress-up with my jewelry.

My boys now often ask why their father and I haven't produced the younger sibling they crave. Their question astonishes me. How sexist and ageist of me to assume that baby lust is reserved for women and adults. What a delight to discover that even adolescent boys appreciate the pleasure a baby gives  -- that downy head tucked in tight, right beneath your chin.

Linda Gray Sexton is the author of four novels and a memoir, Searching for Mercy Street: My Journey Back to My Mother, Anne Sexton.

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