The young Pope Benedict XVI never fell in love with a girl, his brother said in an interview published on Wednesday.
Georg Ratzinger, 87, who is a priest, also said that the pontiff should not hesitate to step down for health reasons.
Asked by German glossy magazine Bunte if the two brothers had been in love with girls when young, said: "No. It was clear to us from an early age that we should take another path and refrain from marriage."
The 84-year-old German-born pope, who is due to begin his first state visit to his homeland on Thursday, should resign if his physical health were to deteriorate, said his elder brother.
"If it is not going well health-wise, my brother should have the courage and the willpower to resign from his position," Ratzinger, 87, said.
"But it hasn't come to that yet, he is very capable of taking action."
Benedict has had no notable health problems since his election following the death of John Paul II, whose final years were marked by noticeable pain and suffering from Parkinson's disease.
Four years before he became pope however, the then cardinal Joseph Ratzinger spent nearly a month in hospital following a brain haemorrhage, according to the German daily Bild. It said he has suffered from fainting spells.
Even Benedict, spiritual leader of the world's 1.2 billion Catholics, is not free of sin, Ratzinger told Bunte.
"Everyone sins -- whether you are the pope or not. My brother of course confesses (his sins) to this day."