Arguments Supporting Stem Cell Research
"The rights of someone already in existence are more important than those of an embryo"
"The embryo hasn't developed properly, and so isn't a human yet"
"The embryos used in the stem cell research are ones from fertility clinics that would otherwise be detroyed"
"People who become pregnant and don't want the baby are able to choose to donate the embryo to research centres, so it isn't against the mother's will - she should decide"
"Stopping someone's suffering is more important than an embryo, who feels no pain or even knows it exists"
Personal experience may also make someone support stem cell research, e.g. if they have a disorder that could be cured from it, and so don't want others to go through the same thing if there is a possible treatment on the way.