Here's an excerpt from Singer's NYT article, A Convenient Truth:
Finally, there is the issue of treating Ashley with dignity. A Los Angeles Times report on Ashley’s treatment began: “This is about Ashley’s dignity. Everybody examining her case seems to agree at least about that.” Her parents write in their blog that Ashley will have more dignity in a body that is healthier and more suited to her state of development, while their critics see her treatment as a violation of her dignity.
But we should reject the premise of this debate. As a parent and grandparent, I find 3-month-old babies adorable, but not dignified. Nor do I believe that getting bigger and older, while remaining at the same mental level, would do anything to change that.
Here’s where things get philosophically interesting. We are always ready to find dignity in human beings, including those whose mental age will never exceed that of an infant, but we don’t attribute dignity to dogs or cats, though they clearly operate at a more advanced mental level than human infants. Just making that comparison provokes outrage in some quarters. But why should dignity always go together with species membership, no matter what the characteristics of the individual may be?
What matters in Ashley’s life is that she should not suffer, and that she should be able to enjoy whatever she is capable of enjoying. Beyond that, she is precious not so much for what she is, but because her parents and siblings love her and care about her. Lofty talk about human dignity should not stand in the way of children like her getting the treatment that is best both for them and their families.