Cardinal Walter Kasper spoke to Spanish publication Religión Digital while in Barcelona for a congress about the pope in mid-November. The event's title was "The contribution of Pope Francis to the theology and pastoral work of the Church."
Religión Digital asked Kasper how the all-male priesthood can be explained to modern people.
"It is difficult today to explain that, but I think it is an ancient tradition, which we keep with the Eastern Churches," he said. "But I think that, with time, the doors will open. In addition, there are already many ministries in the Church for which ordination is not needed."
When the journalist noted some women "are not content with that," the cardinal remarked, "It is clear that some raise their voices, and they have the right to be heard."
The interview, published on Dec. 6, was largely focused on Pope Francis, whom Cdl. Kasper described as a reformer, popular among ordinary people.
"The vast majority of Catholics and the hierarchy are very happy with this Pope," he claimed, "and with his update of the doctrine of the Second Vatican Council."
Kasper said the pope's critics are a small but vocal minority: "They are few, but with new digital media, a little mouse becomes an elephant."
"There are some who criticize him for certain things that the pope says or does — but for no reason, because Francis follows the Gospel," he insisted.
He went on to say, "I am sure that he will continue, despite those few reticents, because the people — the holy, faithful people of God, as Francis says — love him very much and would not accept a return backwards."
Kasper claimed the pontiff is fighting for positive change in the Roman Curia: "It is difficult, because it's a very old institution with centuries behind it, and has grown tremendously. It's hard to change that, but Pope Francis has already done many things."
At one point in the interview, the German cardinal spoke fondly of the Amazon Synod, saying, "I have not participated in the Synod on the Amazon, because I was never even there, but it seems to me that its results have been very good, even for the universal Church."
In the same year, Cdl. Kasper came under fire for remarks about African cardinals, which many found disrespectful and even racist. Vatican journalist Edward Pentin recorded Cdl. Kasper saying of his African confreres, "They should not tell us too much what we have to do."
Kasper was bishop of the Rottenburg-Stuttgart diocese in southwestern Germany from 1989 until 1999, when he was elevated to the rank of cardinal and given a titular see.
The German cardinal is part of the "St. Gallen Mafia," a group of liberal-leaning clergy who began meeting in Sankt Gallen, Switzerland in the 1990s, and who are credited with getting Pope Francis elected.