Pope Francis on Thursday denounced technologies that allow people to transition from one gender to another.

According to Newsday, Francis made his remarks while speaking to the Vatican's bioethics board.

The pope said that “rather than contrast negative interpretations of sexual differences … they want to cancel these differences out altogether, proposing techniques and practices that render them irrelevant for human development and relations.”

These practices “risk dismantling the source of energy that fuels the alliance between men and women and renders them fertile,” he added.

Francis has a mixed record on transgender rights. While he has said that priests should minister to the LGBT community, he's also drawn a distinction between ministering to transgender people and “indoctrination.”

“It is one thing if a person has this tendency and also changes sex. It's another thing to teach this in school to change mentalities. This is what I call 'ideological colonization,'” Francis told reporters last year.

Also last year, as Italy debated whether to recognize gay and lesbian couples with civil unions, Pope Francis reiterated the Roman Catholic Church's opposition to marriage equality.

“The family, founded on indissoluble matrimony that unites and allows procreation, is part of God's dream and that of his church for the salvation of humanity,” he said.