Zen,
Firstly, that child WILL find a loving home. There are many, many examples of just such cases and sure the babies are more difficult to place but very, very few are ever not adopted.
To use your analogy, that a to bring a child into the world with an infectious disease that will spread to others must be stopped or that a child will lead a very difficult life if it has certain maladies.
Does this mean that doctors should have syringes ready for every AIDS diagnosed patient, or cancer(it very painful) and after telling them the diagnosis they are immediately euthanized??? Does that make sense to you???
Remember from a pro-life viewpoint, all life is equal. We believe that life begins at conception and so anything you want to do to the fetus, in our view, should be done to a 5, 15, 25, or 65 year old.
You claim I have a contradiction in my philosophy, however, I don't see it in your post.
I guess you'll have to be more explicit. That is, I say this and then make a point that immediately counters the previous point.