Many churches teach that embryonic stem cell research is strictly wrong, while adult stem cell research is alright. What is the biblical basis for this teaching and why are the two distinguished?
This article gives a pretty good summary of the foundations, though I'm not going to endorse the argument it makes.
Those Christians who believe that life begins at the moment of conception, and that a cell cluster five days past conception is the equivalent of a human being, equate the use of embryonic stem cells with murder. Use of adult stem cells does not kill the donor.
There are other questions that address the biblical foundation for "life begins at conception".