Pope Benedict XVI has paid tribute to 17th-Century astronomer Galileo Galilei, whose scientific theories once drew the wrath of the Catholic Church.
The Pope was speaking at events marking the 400th anniversary of Galileo's earliest observations with a telescope.
He said an understanding of the laws of nature could stimulate appreciation of God's work.
In 1992, Pope John Paul said the church's denunciation of Galileo's work had been a tragic error.
Galileo used his scientific methods to demonstrate that the Earth revolved around the Sun and not the other way around.
This is now:
The pope has sparked controversy by saying defending heterosexuality is as important as saving the world's rainforests from destruction.
Speaking in a holiday address to the Curia, the Vatican's central administration, Benedict said yesterday the church viewed the distinction between men and women as central to human nature, and "asks that this order, set down by creation, be respected".
The church, he said, "should protect man from the destruction of himself. A sort of ecology of man was needed, he said," adding: "The tropical forests do deserve our protection; but man, as a creature, does not deserve any less."
Benedict focused his attack on what he described as "gender" theories, "which lead towards the definitive emancipation of man from creation and the creator".
Homosexual groups in Italy called the speech an unfounded attack on homosexuality and, more specifically, on people who undergo sex changes. "What keeps the pope awake at night is the idea that human beings might be able to seek out their own sexual identity in a bid to have a happy life," said Franco Grillini, head of Gaynet.
"The speech has no scientific basis," said Aurelio Mancuso, head of Arcigay. "A divine programme for men and women is out of line with nature, where the roles are not so clear."
The Catholic church teaches that while homosexuality is not sinful, homosexual acts are. It opposes gay marriage, and in October a leading Vatican official called homosexuality "a deviation, an irregularity, a wound".
Seriously? Homosexuality is a "wound" that "threatens the destruction" of humankind?