"Homosexuality is a defective manner of expressing sexuality because this [sex] has a structure and a purpose, which is procreation," said the Rev. Fernando Sebastian, 85.
He compared being gay to his own hypertension, a medical condition, The Local.es reported Monday.
"It's a defect that I have to try and correct in whatever way I can," Sebastian said. "To say that homosexuality is a defect is not an insult. It helps because in many cases of homosexuality it is possible to recover and become normal with the right treatment."
In July, Pope Francis said of homosexuals, "If they accept the Lord and have good will, who am I to judge them?"
Sebastian, whose appointment as cardinal becomes effective in February, said his comments were not in contradiction to those of the pope.
Francis was "very respectful and holds all people in high esteem," Sebastian said, but "it's one thing to be compassionate towards a homosexual person and another thing to morally justify the practice of that homosexuality."