Antibiotics are not created from human beings with souls. They are developed from either natural sources, or a synthesis of materials that mimic natural sources. Not an apt analogy.
As for your argument about IVF, intimating that the Church's view somehow argues that couples with fertility problems DESERVE to be barren; it's also an incorrect analogy.
It's not an argument that infertile couple DESERVE to be barren, they just ARE. The question is whether or not we need NON-procreative means to assist them in being parents. We don't have the RIGHT to have children. Some of us can bear our own children some can't. If abortion were not so readily available, and if the adoption laws in this country weren't so squirrely, there would be more children to adopt.
In my opinion, the biggest problem with adoption laws right now is that they can leave prospective adoptive parents in fear that their child could be taken away from them by one or the other natural parent who decided to change his or her mind several years after the birth. So, as a result, many people who might be willing to adopt don't want to risk that heartache. I believe that's why so many adopt from outside the US. It's MUCH less likely that the birth parents will come looking for the baby to take it back.
It is an apt anology. Anti-biotics are an “unnatural” means to end a disease. Infertility is a disease (a sydrome, really).
IVF joins genetic material, just exactly like normal sex does -— sperm swims to egg. All that changes is the location of the event. The embryo is still transferred, and God either lets it implant in the mother and prosper or not, just like normal sex.
There are all sorts of moral issues created by IVF (chiefly, too many embryos), but in reputable clinics, these events are avoided.