IMO the opinions people are holding are:
- There should be no abortion or selection of embryos under any circumstances.
- A woman should have the right to all information science can provide her with about the genes of her embryo or foetus and have the right to abort or select for any reason, including aborting girls because you only want boys, Asperger's syndome children etc.
- There should be some form of abortion or selection for genetic reasons to make society better by having cleverer, fitter children and it is wrong for people to actively choose a deaf child (the OP's first post).
- There are some things you should not be allowed to abort or select for (for example, sex of the baby) and some things that you should be allowed to abort for (for example, very serious fatal diseases) and the areas in between are a matter for society to debate.
I suspect most people fall into group 4, and the debate is really about what groups of vulnerable people are up for grabs in this genetic selection process. It is clearly going to be highly offensive to many people.
I don't think autism and ASD are red herrings; they are the group that tests are being developed for, and they are not, if I understand it correctly, selection of embryos, as it is a test that can only be done after pregnancy begins; it is about the abortion of autistic people.
It is all very well talking about hypothetical situations, but as Riven pointed out, this selection process is already happening. We already abort children with cleft palate, even though this is usually correctable with surgery. In other countries, people already abort girls because they view them as inferior.
IMO breast cancer is the red herring, because very few people in society are seeking to ban pre-implantation genetic screening for breast cancer. It seems to me that very few people in society are fighting for the rights of people who have a cleft palate or asperger's. Our view of what constitutes 'normal' and what constitutes 'special' is growing all the time, and that is only a good thing if we don't believe that 'special' people can be aborted after the legal limit has passed.
We have to say where we draw the line, because there is a line somewhere between wanting to prevent the pain of breast cancer and wanting to promote eugenics. The OP and many others in this society have crossed that line, and I find it terrifying.