Some of the proponents of transhumanism are vehemently anti-Christian and try to paint an image of Christianity as being completely against scientific advancement.
As some have already pointed out, there are many instances of transhumanism that the church actively supports. Prosthetic limbs, glasses, modern healthcare, etc.
Where the battle occurs and should occur is with respect to the sanctity of human life. Most Christians don't oppose stem cell research, but they do oppose creating human embryos only to kill them in research.
Genetic engineering is an area where we need to tread carefully. I suspect most Christians would fully support genetic modification treatments to overcome genetic diseases.
But if you start doing things like mixing human and animal DNA, is that not bestiality?
If we get to the point where we understand genetics that we can safely modify the creator's design, should we? There is no scriptural prohibition that I see. How do you get to a safe understanding without having horror stories and mistakes along the way?
We've modified wheat.
We've modified livestock.
We've done amazing things with modern medicine.
As to where we should stop that train, I think we're on our own.
Danny in post #11 is right. There are some aspects of “Transhumanism” that are not morally objectionable or anti-Christian. The problems arise when in the hands grossly unmoral society or government this science is used for perverted reasons and with horrific and morally dangerous results.
For instance:
(1)Transplanting an eye from a deceased baby to help a living baby see is a good thing. But when greed leads people to encourage painful murder (abortions) (with no regard for the human life they are extinguishing) in order to harvest the eyes to sell them for profit.... it all then becomes morally wrong.
(2)To some scientists the goal of Transhumanism is Transcendence or to become something other than human. To what are they trying to transcend to? The answer is as old as the forbidden tree in the Garden of Eden, they seek to become “gods”. We already know what our God thinks of this, and what His inevitable punishment for it is. The truth is that no one will become a “god”, that is merely the same lie that Satan told to Adam and Eve. But it is a big enough temptation that when a world government becomes able to convince people that if they, for instance, take the offered nanobot injection they will be invincible and live forever, few people will reject it, and they will become totally controlled.
If you do not think that Transhumanism is dangerous watch this video of a talk given by Chuck Missler, evangelical Christian, Bible teacher, engineer, and former businessman: https://www.youtube.com/watch?v=xkJe9re-8AI