Time is running out for my friend. While we are sitting at lunch, she casually mentions that she and her husband are thinking of "starting a family." What she means is that her biological clock has begun its countdown, and she is being forced to consider the prospect of motherhood.

"We're taking a survey," she says, half joking. "Do you think I should have a baby?"

"It will change your life," I say carefully, keeping my tone neutral.

"I know," she says. "No more sleeping in on Saturdays, no more spontaneous vacations......"

But that is not what I mean at all. I try to decide what to tell her. I want her to know what she will never learn in childbirth classes: that the physical wounds of childbearing heal, but that becoming a mother will leave an emotional wound so raw that she will be forever vulnerable. I consider warning her that she will never read a newspaper again without asking, "What if that had been my child?" That every plane crash, every fire, will haunt her. That when she sees pictures of starving children, she will wonder if anything could be worse than watching your child die.

I look at her manicured nails and stylish suit and think that no matter how sophisticated she is, becoming a mother will reduce her to the primitive level of a bear protecting her cub. That an urgent call of "Mommy!" will cause her to drop her best crystal without a moment's hesitation.

I feel I should warn her that no matter how many years she has invested in her career, she will be professionally derailed by motherhood. She might arrange for childcare, but one day she will be going into an important business meeting, and she will think about her baby's sweet smell. She will have to use every ounce of discipline to keep from running home, just to make sure her child is all right.

I want my friend to know that everyday decisions will no longer be routine. That a 5-year-old boy's desire to go to the men's room rather than the women's at a restaurant will become a major dilemma. That issues of independence and gender identity will be weighed against the prospect that a child molester may be lurking in the rest room. However decisive she may be at the office, she will second-guess herself constantly as a mother.

Looking at my attractive friend, I want to assure her that eventually she will shed the pounds of pregnancy, but she will never feel the same about herself. That her life, now so important, will be of less value to her once she has a child. That she would give it up in a moment to save her offspring, but will also begin to hope for more years -- not to accomplish her own dreams, but to watch her child accomplish his.

My friend's relationship with her husband will change, but not in the way she thinks. I wish she could understand how much more you can love a man who is always careful to powder the baby or who never hesitates to play with his son or daughter. I think she should know that she will fall in love with her husband again for reasons she now finds very unromantic.

I want to describe to my friend the exhilaration of seeing your child learn to hit a baseball. I want to capture for her the belly laugh of a baby who is touching the soft fur of a dog for the first time. I want her to taste the joy that is so real it hurts.

My friend's quizzical look makes me realize that tears have formed in my eyes. "You'll never regret it," I say finally. Then, squeezing my friend's hand, I offer a prayer for her and for me and all the mere mortal women who stumble their way into this holiest of callings.