Max Rossi/Reuters

This week in Rome, the Vatican is holding its biggest meeting since 1985—an "extraordinary synod of bishops," only the third gathering of its kind in history. The 253 attendees include cardinals, bishops, theological experts, and a few dozen laypeople who are there to observe or testify.

And in large part, they're there to talk about sex.

The synod is focused on issues related to the family, which may or may not include discussions of divorce, priestly celibacy, contraception, abortion, and gay marriage. The point of the meeting isn't to make big doctrinal changes; if anything, those will come at a follow-up meeting of even more bishops in October 2015. This gathering is more about starting a conversation on subjects that have often been treated as taboo in the Catholic Church: In his opening remarks, Pope Francis urged the attendees to speak frankly and not consider any topic off-limits.

While the Vatican is keeping the proceedings closed to the press, there have already been a few splashy moments: On Monday, a married couple, Romano and Mavis Pirola, urged the Church to be more welcoming to gay couples. "The Church constantly faces the tension of upholding the truth while expressing compassion and mercy. Families face this tension all the time," they said.

"The central role of sexual intercourse in marriage—now that's not what we bishops talk about, primarily."

During a press conference on Tuesday, Vincent Nichols, the archbishop of Westminster, said that conversations among the bishops have focused on "the central role of sexuality and sexual intercourse in marriage. Now that's not what we bishops talk about, primarily," he noted with a wholesome, priestly laugh, but there has been "a recognition that it is central to the well-being of a marriage."

He spoke about the interventions that have been made by English-speaking bishops so far—speeches that essentially shape the direction of the proceedings. While he didn't name any of the bishops who spoke—Cardinal Lorenzo Baldisseri, the general secretary of the synod, has said the proceedings are being kept confidential to encourage honest, frank discussion—Nichols highlighted one intervention of particular interest.

"Language such as 'living in sin,' 'intrinsically disordered,' or 'contraceptive mentality' are not necessarily words that draw people closer to Christ," Nichols said in summary of one of the anonymous speeches. Those terms are often used to refer to premarital sex, homosexuality, and sex that involves forms of birth control like condoms or the pill. "Marriage is being filtered in harsh language through the Church," he added.

This is the same kind of rhetorical focus that Francis has had in the year and a half since he was elected pope. In July 2013, he famously told reporters, "Who am I to judge?" when asked about his views on gay priests. Last month, he performed the first marriage ceremonies conducted by a pope since 2000; among the 20 brides and 20 grooms were people who already had children and previously lived together. These symbolic gestures have not been followed with substantive changes in Catholic doctrine on homosexuality or premarital sex, but they've helped to set a new tone for the Church: one of openness and acceptance, rather than one of condemnation.

"Language such as 'living in sin': not necessarily words that draw people closer to Christ."

It seems implausible that Church doctrine on issues like divorce is going to change significantly as a result of this synod; in a lengthy report presented before the opening of the meeting, Hungarian Cardinal Péter Erdő blankly stated that "in the case of a (consummated) sacramental marriage, after a divorce, a second marriage recognized by the Church is impossible, while the first spouse is still alive." On other topics, like annulment, it's possible that there will be more of a shift.

But with or without substantive doctrinal changes, this intervention—one that reporters admittedly still have limited information about—suggests there's a softer postural debate happening alongside the pastoral debate. The Church may still consider it a sin to have sex before marriage, but leaders can change the way they talk about it—lighter on the shame, heavier on the spiritual guidance.

As the Church's highest leaders turn their attention toward sex, marriage, and the family, there's one other aspect of this synod that's worth noting. Of the 191 Church officials in attendance, only one is a woman: Sister Margaret Muldoon, the superior general of the Sisters of the Holy Family of Bordeaux.