Last month, South Korea decided to allow research on creating stem cells through human embryonic cloning to resume despite a scandal involving a prominent scientist in the field. Pope Benedict XVI appealed Thursday to South Koreans' "inherent moral sensibility" to reject embryonic stem cell research and human cloning after the country decided to let embryonic stem cell research resume. Benedict also praised South Korea's efforts to halt North Korea's nuclear ambitions in comments to Seoul's new ambassador to the Vatican, Ji-Young Francesco Kim, who presented his credentials to the pontiff.

Separately, the pope noted South Korea's "notable successes in scientific research and development." But he said such research must be carried out with "firm ethical standards" that always respect the dignity of human life.

Stem cells are master cells that can grow into any bodily tissues, which scientists say could lead to revolutionary new cures for hard-to-treat diseases. Benedict noted that the Vatican does not oppose -- and in fact encourages -- somatic stem cell research -- also known as "therapeutic cloning," which uses human eggs specifically for research from which stem cells are harvested.