The Vatican has released new guidance for Roman Catholics on modern sins they should avoid committing, among them polluting the Earth and genetic manipulation.

Monsignor Gianfranco Girotti, the head of the Apostolic Penitentiary, told Vatican newspaper L'Osservatore Romano over the weekend that today's new "modern" sins center on bioethical questions, warning that humans should avoid genetic manipulation, such as stem cell research, which can be "difficult to predict and control."

The church opposes the destruction of embryos and cloning.

Other modern evils, he said, include "ecological offenses," following the Vatican's growing concern over climate change, which it says affects the entire human race.

The Vatican archbishop who talked about the new sins said Catholics offend God not only by stealing or lust, but by ruining the environment.

In recent years, under Pope Benedict XVI and his predecessor John Paul II, the church has held scientific conferences on global warming and has taken steps to make the Vatican more "green."

The church divides sins into categories, among them venial sins which are less serious and mortal sins, which include abortion, adultery and murder.