I missed the beginning, but is she actually arguing that only the absence of an accurate test, or the fear of miscarriage in amniocentesis, has kept babies with Down's being born? Therefore women should be denied access to accurate, safe testing?
I mean, I completely understand her deep desire to defend her son, to not have to justify his existence, her sense that Downs is being regarded as a 'disease', to worry about him living in a world where people like him have stopped being born, to worry about medics pressuring women to terminate, but it seems to come back to a desire to stop people having access to information.