Okay, this thread has been hijacked! You're both forgiven, of course, but to return to the subject for a moment...
The original question ("does some science shatter human dignity") and the statements by Pope Benedict leave wide-open a matter of some critical importance: does a human being have a "soul" that is separate from the physical human, and secondly, if it does, when does that soul become part of the new human?
Because without answering that, then there are always going to be those who opine that -- without a separate soul, or before "ensoulment," the unfinished human really is nothing more than "biological material."
When my tonsils were removed nobody thought to care for them tenderly, or at least give them a Christian burial. They were "biological material." When a person can donate a kidney, or part of their liver, to another person for transplant, we don't consider that we've somehow comingled "souls" in the process, nor do we feel that the donor has lost part of who he essentially is.
Benedict, through his faith, has decided that it is his belief that a human consists of "body and soul," and that ensoulment happens (or at least should be construed as happening, since the Church has not taken an official position) at the moment of conception. (How this "soul" is supposed to operate at that moment, without even a single neuron let alone a nervous system, remains something of a mystery to me.)
It is my opinion (belief?) that what constitutes the human "soul" is the complex nervous system that permits consciousness, and until that nervous system is substantially in place, no human exists, although human biological material certainly does.
And therefore, stem cell research -- even if it uses discarded embryos -- does no violence to human dignity. My views on other such matters (reproductive research, abortion, etc.) are similarly formed.