Question:
My wife wants another child. We’re financially strained as it is, and I think it’s irresponsible to add another mouth to feed when you can’t afford it. Are there no limits to the commandment to “be fruitful and multiply”?
Answer:
You are suggesting that finances should determine how many children we have. If you can’t afford it, don’t have babies. The stork should accept only cash on delivery. Debt and diapers don’t mix. It’s all about the bottom line.
That sounds reasonable. But let’s see if it makes sense.
Let’s say my financial adviser assesses that I can afford to have four children, and no more. So I go ahead and have them. A few years down the road, my situation changes drastically for the worse, and I can no longer pay the bills for a family of six souls. So I call in my youngest and say, “I’m sorry, we made a miscalculation. We thought we could afford you. But you know how unpredictable the market is these days. We’re going to have to let you go.”
How are we supposed to measure how many children we can afford? Can anyone predict what size family we can or can’t fund in the future? Who can say for certain that they can afford even one child?
A family is not a business. It’s about people, not profits. Having a big family means making the choice that our wealth is our children, and though we don’t know what the future holds, we will do all we can to provide for them in every way. If that means taking a few less vacations or having to buy used cars instead of new ones, then the sacrifice is worth it.
There are indeed situations where Jewish law limits our multiplying. If the emotional or physical health of the parents is at risk, or if the strength of their relationship is in question, they may be advised to hold off from having children. But they will determine that together with their spiritual mentor and their health practitioner, not their accountant.
I have often heard people say they wish they could have had more children. I have never heard anyone say they wish they had fewer. Each new soul is a blessing to the world and a blessing to the family. You think you can’t afford to have another one? Perhaps you can’t afford not to.

We live in Vancouver, a ridiculously expensive city. If we have another child, it would mean more than just buying a used car, and not taking vacations at all. It means not seeing grandparents in person because that's two flights away. It means changing where we live so we can afford a roof over our heads, and by doing so, it means going so far away from the Jewish community that we would be outliers. Additionally, having more children, no matter how much we want to, we would not be able to afford Jewish school, something that is really important to my spouse and I.
I wish we could have another. But the sacrifices aren't worth it.
I am happy to hear that Jewish education is a priority for you and your husband. Ultimately we must realize, as the article points out, that we do not know what the future holds. We need to trust G-d that when we fulfill His desire for us to have more children, He will give us the ability to be able to care for them. The Lubavitcher Rebbe explained that we cannot base our predictions of what the future will look like economically, because with every child born a new channel of Parnasah - making a living, is opened for us from Above. This only becomes active, once we have a child - then his or her own unique channel of Divine blessings comes to the parents. Please see here for more about this.