The couple “renews their wedding vows”, and then God decides to create a baby. (As an aside, I’ve found the euphemisms for ‘having sex’ very entertaining.) The couple appears to have no control over pregnancy, and this is really not the case. So when people say, “You have as many children as God wants you to have”, it sounds as if it’s because God creates children, not due to an egg and sperm meeting, dividing, etc. that is the direct result of a sexual act. It somehow absolves people from having to make the decision, because it’s God’s decision and we just have to figure out what he decided.
I think I see where you are going with this, but I don’t want to read too many of my own beliefs into it. I am human, I will no matter what, but I am trying to see it for what you present not for what I believe.
First off, I don’t consider the term “having sexual intercourse” or “having sex” to be nearly descriptive enough in this day and age. In the newer NAB Bible, what Jesus says on the Cross before dying is translated as, “It is finished.” In the older Douay-Rheims version it is worded much better. He says, “It is consummated,” instead. Consummated is much better because it is not just an end, not just finished, but a beginning too. What He does is all-consuming. I don’t think “renews their wedding vows” is a euphemism. We consummate once and every time thereafter re-present that original vow. What happens in consummation can in no way be compared to what a fornicating, contracepting couple or a same sex act has. If those acts are termed, “having sex” then the term’s meaning is lost.
I do agree with you that the act of sexual intercourse is in control of the spouses, however, I still say that no conception is beyond the will of the Father. No matter how much the infertile couple wills it, they cannot join an egg and sperm by will alone. God can.
If I can go back to the concept of freedom and free will:
I’ve also gotten the impression that God’s Will is, or can be, very specific, and in order to do good we must follow this “script” that God has made for our lives. If we do not follow the script, we turn our back on God and do evil. Personally, I will argue day and night against any form of destiny. We are “left in the hand of our own counsel” and our lives have not been predetermined for us. In this vein, I would argue that God has not decided that we should have three kids, or ten, or twenty, or none at all. While most people on this board would argue that having a child is a good thing, that does not directly imply that the converse, not having a child, is evil or out of line with God. Choosing to have a child is not a “good vs. evil” decision.
God is a God of order. Order has a plan. It can’t be a script because a script is made up beforehand. God is outside of time. Nothing He does was ‘before’ or ‘after.’ Everything for God is RIGHT NOW. “In the beginning…” is only our beginning. He has no beginning and no end. I totally agree with you to argue against destiny, very Calvinistic. We are Catholics. Jesus is now. His sacrifice on the cross is NOW, because He is God.
I also agree that God hasn’t
decided our number of children. That is past tense. I do believe he
knows (present tense) all of my children. For that matter, he knows my grandchildren and great-grandchildren, even though in my time they don’t exist. They are not in some “pre-existence” like in Mormon theology. Yet if God is all-knowing then he
knows them too.
I
completely agree that it is not evil to decide not to have a child. It is an important part to all celibates lives. But, they have decided not to “have sex” (termed just for you

) as the way to that end. One of the phrases my husband says in our NFP talk is this, “Sex makes babies, no matter how many people try to tell you it doesn’t.”
The moral question should come from “Can I properly raise this child within my abilities and within the support I receive from my spouse, my family, my friends, and most importantly, from God?”
That is the question NFP couples (and also the “just wing it” Catholic couples) ask every time we engage in sex. Not just every time we think we might be fertile, but every single time. We do ask it though, with one difference. We ask the entire beginning part. We know the support from God is absolute. That is what gives us the courage to engage in sex in the first place.