There's really no issue unless a cloning process actually creates an embryo that has even a non-insignificant fraction of the chance of coming to term as a naturally conceived one. It really does seem tantamount to opposing organ donation rather than opposing the encouragement of abortion. Also, it appears that in the last couple of years there have been several trials started with stem cells. One experimental application has been a cure for AIDS.
I was responding to this hypothetical, which does sound as though it advocates cloning of some sort (embryos being grown in labs):
Here is my philosophy on stem-cell research.
Stem-cell research holds promise to cure disease for thousands of patients. It hold promise to replace dead cells. Paraplegics hold out hope that even paralysis can be cured through the use of stem cells. People oppose stem cell research on the basis, and possibility, that embryos will be grown in labs, and used not to let that life come to fruition but to harvest stem cells. But think about it this way: (and I'm not even sure this is how it works, but let's assume it is considering it is the basis for the opposition) An embryo is grown in a lab, then is used to harvest stem cells. A child with terminal cancer is given these stem cells in a transplant. Without this treatment, the child would have surely died.
^ How is this scenario NOT "creating life". That child can now live their life, instead of dying at a young age. When you grew that embryo, YOU DID CREATE LIFE.
I am aware that isn't how stem cell research is actually conducted.