‘90s FAMILY : When Your Biological Clock Is on ‘Snooze’ : Hers is. She has no yearning to be called Mon, to stay up ‘round the clock, to give up unencumbered vacations, to change diapers. And at 35, she wonders if she ever will.

I keep checking my vital signs, straining for the sound that everyone says must be right around the corner. But there’s only gaping silence. No ticktock, ticktock. No warm fuzzy feelings when I see pictures of plump, smiling babies.

At 35, my biological clock has not kicked in, and that has me worried.

My condition--if you will--flies in the face of common expectations. Subtle but persistent messages inform us that motherhood is still one of the most fulfilling experiences a woman can have.

The papers are full of women who juggle marriage, a rewarding career and children. Friends talk about waking up one day and knowing the hour had come: They were ready to assume the mantle of motherhood.

The future looms ominous. Didn’t a famous, fortysomething TV anchorwoman announce a much-ballyhooed hiatus from her high-paying job to devote more time to trying to have a baby? Will I ruefully be doing the same in seven years, cursing the fact that I didn’t take advantage of my supple ovaries when I had the chance?

Maybe. But all I know is, I’m not ready to have children right now, and the sands in the hourglass of my fertility trickle lower with each year that I wait.

Perhaps I will never feel that fierce yearning to be a mother but will become one anyway and be happy that I did. Maybe my husband and I will remain childless--he is ambivalent anyway. Maybe we will adopt--there are too many unwanted babies in this world already.

Yeah, I know. I’m selfish. Ungrateful to relatives who want to hear the pitter-patter of little feet. Some kind of a freak to acquaintances who long ago birthed three kids and moved to the suburbs.

Oh, and so First World. In many parts of the world, babies aren’t always planned meticulously. If you wait until you’re financially ready, that day may never arrive. Sometimes babies just come and everyone adjusts a little bit and goes on living.

Those who have traveled know what I mean. When I was in Albania last year, women would crowd around and ask how many kids my husband and I had.

“None,” I responded, reaching into my pocket to make sure I hadn’t forgotten to pack my contraceptive pills. “We’ve only been married two years.”

“Well, don’t be too sad,” they would cluck. “If you keep trying, you’re bound to have luck sooner or later.”

My mother, 74, is surprisingly sagacious about the whole thing. She never put any pressure on me to get married and she’s never put any pressure on me to have a child.

This is the woman who told me to stop kidding when I showed her my engagement ring and told her I was getting married. “C’mon, Denise, tell us the truth, where did you get that ring?” she wheedled.

And now that she is tied up with baby-sitting my 1-year-old niece, Laurence, my mother has other things on her mind besides my womb.

“If you intend me to help with your kids, you’d better hurry up and have some, because I’m not getting any younger” is the most she’ll say.

“Yes, I know,” I mutter darkly.

This is on my mind a lot already; I don’t need to be reminded. We are both getting older, but age does not bring any clear answer to my dilemma.

I draw some consolation from the fact that my mother, a retired OB-GYN nurse, had me, her first child, at 39. My little sister came when she was 44. I come from rugged Franco-Slavic gynecological stock.

Don’t get me wrong, I’m no W.C. Fields. I love my nieces and nephew and marvel at their beauty and intelligence. But am I ready to change diapers and stay up all night? Not since I stopped baby-sitting as a teen-ager.

Sorry, but Henry Jaglom’s film “Babyfever” does not speak to me. I like babies on principle, can even imagine having them one day, in an abstract kind of way. But I was very conscious of our unencumbered state when we booked a two-week trip to Crete and Santorini recently.

How could we manage such a vacation with children? How will I ever be able to devote enough attention to my career and a baby? I have this sneaking suspicion I would find it hard to leave an infant in day care.

Heck, I didn’t even get a dog until age 33 because I didn’t feel I could offer it enough quality time.

I stand in awe of working friends who struggle to juggle kids and cooking and piano lessons and PTA and husbands while caring for their aging parents. Rare is the time they have to read a book or go to the gym. Or have money to burn on silly personal things like that eight-volume Encyclopedia of Philosophy we purchased last year.

But on the other hand, do I envision myself with children at age 50? Do I picture us with a family gathered to eat Thanksgiving dinner in the year 2005? If so, I’d better get serious soon.

The other evening, I came home from work late. Exhausted, I ate chips for dinner and slid between the sheets to read Susan Straight’s great novel, “Aquaboogie.”

It was a luxurious feeling, and a somewhat guilty pleasure. Across Los Angeles, harried mothers were coaxing spoonfuls of creamed spinach into their babies’ mouths, giving baths and helping with homework.

“I have to get it out of my system,” I explained to my husband, holding up the book. “One day, I’ll be ready for children.”

Maybe.