Pope Benedict XVI warned that advances in biotechnology may lead to practices harming human dignity and called for vigilance on the medical application of scientific discoveries.

“The new possibilities offered by biotechnology and medicine often put us in difficult situations in which we are walking on thin ice,” Benedict said in a statement addressed to the new German ambassador to the Holy See.

“We have the duty to diligently study up to what point these methods can help humans and where they amount to a manipulation of man, to a violation of his integrity and dignity,” the pope said.

The pontiff said that although humanity should not reject these scientific developments, it should remain vigilant.

“Once you begin to discriminate ... between lives that are worth living and those that are not, no phase of life will be spared, even less so old age and illness,” Benedict said.

In February 2009, the Vatican had already condemned the practice of discriminating through genetic selection.

The Vatican fears that progress in biotechnology will multiply genetic interventions aimed at “improving” the human race, such as the elimination of certain diseases through prenatal tests and abortions.