The value of the scientific discoveries which have had the biggest impact in the quest to prolong human life is universally accepted.
Vaccinations are routinely used as a shield to protect us from potentially lethal diseases. Antibiotics are commonly - perhaps too commonly - dispensed to destroy harmful bacteria. Outside of the medical field, improvements in sanitation have saved many lives.
A breakthrough by South Korean scientists last week has similar life-saving potential. But the achievement is highly controversial. This is because it is in the sensitive area of stem-cell research.
The team in Seoul, led by Hwang Woo-suk, was the first in the world to clone a human embryo last year. On Friday, it revealed it had created the first embryonic stem cells which genetically match patients suffering disease or injury.
This is a big step forward in research and will, hopefully, see stem cells used to cure heart disease, cancer and Alzheimer's disease, among others. The genetic match makes it less likely future stem-cell treatments would be rejected by the immune systems of patients receiving them.
The research has rightly been acclaimed by scientists around the world as an important and exciting achievement. One pioneer in the field went so far as to describe it as a scientific revolution.