My husband and I are blessed to be expecting a child this fall. Yet, when I look at the two children we have, I am filled with fear for our anticipated third.

It’s irrational but soul-deep, and the only comfort I have as we wait and prepare is a thing that feels so fragile I am almost breathless.

I look at the lengthening limbs of our oldest, and I marvel that that forearm once fit in the palm of my hand. I see how he leans into his pencil as he draws, moving images from his mind’s eye to the white paper through careful strokes. I watch when he thinks I’m not, when he puts aside all reticence to act out the silly and absurd for his younger brother’s entertainment.

And as for our second son, a full nine years younger than the first, I marvel at the dimples on the backs of his knees. I lock safe the memory of how he used to pronounce his Rs as Vs, including when he would say his own name.

I am not a particularly sentimental woman. But looking at our two sons, our beautiful and imperfect sons, I am filled with such love that I can only wonder at the impossibility of doing it again. How could we ever hope to pull it off one more time?

We went many years between our first and second partly because of this very fear. We were so grateful just to have the one, and the three of us were such a happy family – why mess with perfection?

Then the second arrived, transforming all of us individually and as a household into something new (and louder). And I can’t imagine being any happier than I am. Even with the undeniable challenges unique to toddlerhood, childcare and too-few bedrooms, I think, “My G-d, how lucky we are. We fooled the universe a second time and slipped through more blessed.”

And now we await our third. I had jokingly said that we decided to have our second child in a sort of going-out-of-business sale. Joke’s on me, I suppose. We are thrilled beyond measure — and more afraid than I think we’ve ever been before. Because how can we possibly expect to bring such a creation into this world a third time?

I repeat: I have no real gift for mawkishness. But consider the graceful lines of your child’s femur. Or how his eyelashes rest on his cheek. Or how it feels when he says something to indicate he actually listens to you. Our children are nothing short of miracles, and it takes chutzpah to think we might be so blessed as to make even one.

I feel like the English word “faith” is not a word you hear often among Jews. I can think of nothing better, though, to describe what we as parents must have deep within us. Certainly, intentionally having children reflects profound and deep-seated optimism in the future. But we must also have faith that our bodies — these God-given instruments — are up to the task of creating hearts with four valves, the ridge of the nose and the dimples on the backs of the knees.

And it takes faith to believe we have the capacity to grow our love again and again, to include more and more people, more and more uniqueness. I am overwhelmed by the obligation of my soul to continue to stretch.

And yet it has so far. And I have faith that it will again — just one more time.