Memo to Marissa Mayer

07/18/2012 05:19 pm ET | Updated Sep 17, 2012

Today's news commentators are on fire with your "having it all" now that you are Yahoo's new CEO and a mother-to-be. Truly, I wish you well.

At the same time, I know for certain that you cannot have it all. My reasoning is simple: The CEO position will take your all and your child will want your all. There isn't enough of you to give it all to both. This isn't to say you shouldn't go for it and take on the high profile CEO position and happily have your baby. Just do it knowing something has to give, and it may be your sense of peace when you realize your child is experiencing the world without you.

You are a highly talented, dynamic woman, as evidenced by your being named one of the 50 most powerful women under 40 in the business world last year. Now you will be the youngest CEO of a Fortune 500 firm. You know your stuff.

But there's something you don't know yet. It is that our very being, inside out, changes when we have babies. Resting, exhausted, sweaty, post-pain and proud in your hospital bed, you'll look into the face of your newborn infant and you'll be overcome with a love like none you've ever experienced. Any mother can tell you this. It is overwhelming, a shedding of your self in a way that you cannot imagine until you're there.

You will spend your maternity leave loving that sweet-breathed creature, listening for the rhythmic sound of healthy breathing, making sure you give enough milk and tickles, and you will learn to deeply inhale the unique fragrance of your baby fresh from a bath, smothered in baby powder. There's nothing in the world like that smell.

And then you will have to say goodbye to that infant day after day, leaving your child in the care of a qualified nurse or nanny. You will miss 80 percent of your baby's life. You will be sick with panic when you feel the warm temples of your infant in the middle of the night, knowing that a fever is brewing and you won't be there to attend to it. Of course, you will have qualified people on hand, but it won't be you.

You will get dressed for work feeling slightly nauseous, but rationalize the worry away for now. You have to keep your mind focused as you walk into the office, difficult decisions ahead, tough meetings to attend to, your responsibilities heavy and real. You will have your hands full as CEO.

I understand, fundamentally, what your life will be like. While I was not the amazing CEO of a huge company, I had a full-time demanding career in leadership positions from the time my two sons were school-aged boys. I now understand that I gave up plenty by allowing work to be my focus for 70 percent of my waking hours. Did my kids turn out well? Yes. Did I serve as a great role model of hard work and personal discipline? Absolutely, although I know they have holes in their hearts where I should have been. I know that, and I live with some regret because of my choices.

All this to say, don't believe the well-intentioned enthusiasts when they say you can have it all. You simply cannot. We take our life in our hands, make our choices and have what we have -- just not all.

Congratulations and best wishes as a CEO and mother.

Martha Nelson is an award-winning journalist and a former educator, nonprofit executive, chef, and musician. Her first novel, Black Chokeberry, was published in April 2012 and is available everywhere including from her website,

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