"Mommy, when am I going to get my baby?" my 3-year-old asked this afternoon.

Simon was not asking about when he will have his own child. He wanted to know when he would have a baby brother or sister. This past year, families at his day-care center experienced a baby boom. Three of his classmates got new baby brothers and sisters, drawing my son's attention and longing. Then, today, two brothers from down the street came over to play. Their Mom was visibly pregnant. I told Simon that his friends, now 3 and 5, soon would have a baby brother or sister. That prompted the question. I had no easy answer.

"Simon," I said, "Mommy and Daddy don't plan to have more babies. You are very special, and we're so happy to have you."

He nodded, then asked, "Can I have a baby brother or sister?"

"No, I'm a little old. Do you understand?"

"No," said my son, who loves to play with and coo at his friends' baby siblings. He cuddled in my lap and then scooted off to play with a truck.

Decision Time

If my husband and I were to have had a second child, the best time to make the decision was immediately after Simon's birth. Even then, it was a risky proposition. After eight months of trying and a few fertility treatments, I became pregnant on an off-cycle. I had Simon at age 43. After his birth, I was conflicted about having another child. On one hand, I felt like we should just count our blessings. Not only did we have a child--we had a healthy one.

Yet, there was this pang. I definitely had a longing for more than one child.

baby brothersI grew up as the youngest of three children. I had gushy memories of playing with my brothers along with recollections of merciless teasing. I also had heartache when it came to siblinghood. My brother Kevin was killed in a car accident when he was 23, and I, 21. I struggled to cope with his death for years. Growing up, Kevin and I were inseparable, as much best friends as siblings. How could I not want my son to have a chance at growing up with a brother or sister? Siblings can be rivals and end up more like acquaintances than family. But they also can grow up like Kevin and I did. We wanted to raise our families side by side.

My husband, I, and my doctors, were initially thrilled at how well Simon's birth went. I had a normal delivery with no complications. We talked excitedly about trying for a second baby. But six weeks later, there was a sour note. I developed post-partum depression, which strikes 10 to 20 percent of new mothers a year. I was overanxious, depressed, and at times, irrational for at least three weeks. I was, as I later found out, particularly at risk because of experiencing short bouts of depression on the first and second anniversaries of my brother's death. Some researchers also say taking fertility drugs and giving birth over age 35 can make a woman more prone to post-partum depression.

With help from my husband, a counselor, and my growing connection to Judaism, I mostly came out of the depression within three weeks after my diagnosis. But post-partum depression cast pallor on the idea of having a second baby. There was a 50-percent chance it could happen again, and this time, Simon would be old enough to know something was wrong with his Mom. Other factors, including finances, weighed into our decision. Doctors, too, said we would need to work quickly given my age. We worried about the effect on Simon if I became pregnant during his first year of life. My husband said he was OK with having just one child, and I, a little later, felt the same way.

More Than Happy with One

Our window for trying for a second baby has long passed. I'm closer to 50 than 40. Simon's question today brought back that old pang, but it quickly faded. My husband and I have a wonderful gift--the son we have. But it is not an easy decision to declare that one is enough.

Over time, I hope Simon will make bonds with peers that will last for life. I work to make sure Simon's parents are not his only social contact. We regularly get together with other children. I have hope, too, for what our temple community might give Simon. The more we go to services and events, the more our temple feels like a second family. If I were 10 years younger, make that 15, I would have loved to have had more children. But I prefer to focus on what I have now. Gaining a husband and a son in the last five years was the most beautiful kind of beshert (destiny).

Read more about family size with this look at a Jewish custom to have three kids.

Linda K. Wertheimer

Linda K. Wertheimer, a veteran journalist from Lexington, Mass., is writing a memoir about how the loss of her brother led her deeper into Judaism. She writes about faith and family on her blog at www.jewishmuse.com . Find Linda on twitter as @lindakwert.