If anyone clicks on my profile, they might notice that I have "disability rights" listed as one of my interests. I think it is necessary to explain my position here. I do consider myself a "transhumanist" because that philosophy is closely in-line with the outlook I've developed independently of even learning of transhumanism -- but I am not in favor of some of the more eugenic-like aspects of some transhumanist lines of thought.
I do not agree with the notion of fiddling with someone's mental / emotional characteristics before they are born. Personality is one of the main factors that determines a person's behavior, and personality is not, by and large, something we are born with. We are born with tendencies toward certain directions, but in many ways, the "self" develops in response to environmental variables.
What I DO support are genetic / in-utero interventions for conditions that actually kill people.
I am opposed to the notion of playing with genes in the hopes of influencing temperament -- the world needs introverts and extroverts, salesmen and inventors, librarians and actors, naturalists and artists. I can understand a parent wanting their child to have maximum chances for success, but I don't think it is right to impose a definition of success on someone who hasn't even been born yet.
Plenty of parents would like their child to someday take over the family business -- but rather than creating some sort of custom-designed offspring who is likely to eagerly follow in the family legacy, I think it is far better for the parent to let their child grow and develop as an individual and then let the child decide what they want to do with him or herself in the long term.
So, how does this relate to disability rights?
The way I see it, human existence is like a huge and complex construct. There are tremendous benefits to having different perspectives as to the nature of this "existence construct". If everyone had exactly the same set of abilities, likes, dislikes, interests, attention patterns, etc., it's likely that many vital aspects of society would cease to function. If everyone were a people-oriented extrovert with a tremendous desire to belong, a lot of scientific developments would cease because everyone would be too busy planning cocktail parties. If there were no Deaf people, we would lose an opportunity to observe how language can develop in a visual (sign language) rather than auditory medium.
To bring this to a personal level, I absolutely am not in favor of manipulating the brains of fetuses if it is determined that the child is going to be autistic. Autism, by and large, results in a developmental trajectory that is extremely difficult to predict. To assume that just because someone has an autistic brain structure that they are going to lead "miserable" lives, "devastate" (how I hate that word!) their families, and "never contribute anything" is ridiculous.
There's no way to know this when a person is conceived or born. Many people with autism are very happy, very successful in their chosen ways, and run into most of our difficulties due to a lack of understanding of our communication style (or due to the existence of social institutions that we would really be better off without). I am certainly in favor of learning how autistic brains are structured, but I think it would be tragic if we sought to eliminate these differences in brain structure.
My own autistic spectrum "disorder" has not turned my existence into a tragic waste. I would be infuriated if anyone decided that I should be forced to undergo some sort of therapy to make my brain "normal". My brain-difference doesn't make it impossible for me to breathe, wonder, think, or live. I fully support technologies that might be able to prevent severe and deadly birth defects (as in, things that result in a child going straight from the womb into the ICU), but I do not support the notion that anyone can decide FOR a person how their brain is going to be configured, what their personality is going to be like, etc.*
One danger in "espousing a philosophy" -- transhumanism or any other -- can come from not differentiating sufficiently between reasonable, ethical goals and unreasonable, unethical goals. In a sense, growing up differently-brained has prepared me to work toward the right to continue existing even when I'm elderly -- I feel that in some ways I've had to justify my existence all along!
In embracing transhumanist ideas, I am not in any way suggesting that everything mankind doesn't alter or influence is somehow bad. I support recycling efforts and nature preserves (as in, plots of land set aside to grow wild and allow nonhuman native life to flourish, not elephant jelly!), and I think that the randomness inherent in human reproduction is essential to our evolution as a species.
I think there are indeed some things we humans should not "mess with" -- but the aging process isn't one of these things. Let the trees grow, save the baby whales, DON'T tell me my brain structure is somehow inferior and in need of elimination from the human gene pool -- but certainly work toward cures for things like diabetes, cystic fibrosis, AIDS, cancer, Alzheimer's, kidney failure, liver disease, and aging that result in actual bodily damage and death.
Supporting disability rights doesn't mean supporting the elimination of everything that might be remotely considered a "disability". Some transhumanists may disagree with me on this, but I say that if something doesn't kill a person or (beyond any shadow of a doubt) drive them to murder or torture, then we ought to look very carefully at how we deal with it.
However, I know that death is bad. I know that dying of age-related illness is no picnic in the park -- some people "go" quickly, due to a freak heart attack or whatnot, but many others just watch themselves deteriorate over a period of years, sometimes many years. The illnesses and infirmity of old age do not represent positive diversity -- rather, they represent an involuntary loss of health concluded with the absolute loss of a person. Someone can live happily and productively using sign language, being autistic, using a wheelchair, etc. -- but it's difficult to be happy and productive in any sense when you are dead, or when your brain tissue is literally destroyed by something like Alzheimer's.
In my support of transhumanist ideals, I support the rights of all people regardless of age, regardless of difference from the "typical" to exist for as long as they would like to exist.
* The only exceptions I make to the "don't mess with people's brains" dictate I follow is in the case of things like sociopathic tendencies, pedophilia, etc. Diversity does not mean we need to accept abusers, rapists, murderers, and child molesters.