I think that's kind of the whole idea of transhumanism it opens up what it means to be humanism, since humanism has it's roots in christian theology and the general anthropocentrism and sacred humanity that accompanies renaissance Christianity. Transhumanism is an attempt to redefine humanity in the context of new technologies that will surely change what it means to be human. We already have the technology and foundational science for a self-determined evolution, conscious selection instead of Darwinian natural selection. Eugenics was failed scientific pursuit because it was based on deep inherent genetic traits particular to human ethnic groups and those traits just aren't there, i.e. there is no superior aryan skull shape.
There are, however, genetic flaws in the body. Susceptibility to disease, various forms of deformities and disabilities, all sorts of things. Eugenics was meant to produce a specific population of humanity that would be superior to all others, the transhumanist ideal is using science and technology to remove all suffering from all people. Idealist for sure and I have my own qualms with it but it is if anything more inclusive than humanism. Are cloned humans actually humans? Do they possess the same human dignity as those humans who are created "naturally"? There are scientists who are dedicated to uploading the human mind into computers; if there is no physical body, or if that body is composed of processors and microchips is that a human? transhumanism says yes, and I would have to agree.
As far as theism or divinity in transhumanism. Transhumanism could be seen as an attempt to "play god" a la Frankenstein (a great (trans)humanist story), I like to think (assuming there is a divine higher power) that maybe we were given these obnoxiously large and complicated brains so that we could piece together the ridiculous puzzle that is our existence. And now that we have pretty much figured out life and can start making some and altering it (again biological self-determination), it's kind of like an invitation to finish, or at least cooperate in the grand work of life. Like for the past millions of years of life god has just been grooming and guiding earth lifeforms and now god say "I've shown you the ropes, I'll let you take it from here."
We are just the universe experiencing itself and we're becoming self-aware and as we become self-aware then so is the universe itself and after self-awareness comes self-creation. Think of children; the younger years children usually just mirror and follow their parents. As they grow they start to form into there own person, first they start questioning and exploring (insert awkward middle school phase here) and then they find their passions and drives and they become a full on person no longer dependent nor emulating their parents. And if the universe is fractal, as the great mystics of history say "as above, so below" then it's entirely possible this is what is happening.
That of course is all just my own thoughts and in no way a statement of cosmic truth.
