It was four years ago at this very moment that I was in the final stages of the “pushing” part of my labor, and mere hours away from being rolled into the operating room–shaking like a leaf from all the medication–for an emergency c-section, to welcome my son. My first baby.

Sweet not-so-baby boy, happy fourth birthday.

Having your first child isn’t so much “life changing” as it is “life restarting.” The old You is a a snake skin shed in the sand. The preface to the novel. The old friend about whom you reminisce briefly before remembering how different you two now are.

As moms, we grudgingly leave our old selves behind when Motherhood begins. It’s a shattering and instantaneous shift to the Unknown starting at the very moment we hold our child in our arms.

I once read about a study that says that children leave biological markers in their mother’s blood and brain that forever stay with her, changing her actual biological makeup. Traces of your baby, literally living within you for the rest of your life.

So we’re not crazy when we tell other people we literally feel our child in our hearts. We’re not imagining it. Our bodies, our Selves, are literally changed.

So on this fourth year celebration for our family–and on each of the milestones you celebrate with yours–let us tip our hats to science, who proved what we mothers have known all along:  That, though we are the ones who are giving birth, it is also we who end up getting so much more.Happy birthday, buddy. Love you with every changed cell in my body.