The short piece asks several intelligent questions, but they are related to the practical influence of disability on individuals and families, and the responses a humane society should make.
However, to when we speak out on issues like this, we are "raging against the machine." The "wrongful birth" mindset implies that disability is not a condition to be compensated for, but rather the declaration that a particular human life was an error.
And we "rage against the machine because, unless people have experienced disability in their lives, whether personally or through a friend or relative, they see disability as totally negative.
There is an additional factor: the disability experience must be a positive one (i.e., the person with a disability must be happy, and preferably accomplished and productive).
Otherwise, disability is a negative, one to be prevented by abortion, infanticide ( thank you, Professor Singe r), or euthanasia ( over to you, Dr. Kervorkian ).
To declare otherwise may be choosing to speak against the tide of history, against the utilitarian concept of 9-out-of-10 Down Syndrome children being aborted, against unacknowledged sex selection by abortion, and against the dark promises of genetic manipulation.