Pope Francis urged bishops to speak their minds about contentious issues like contraception, gays, marriage, and divorce at the start Monday of a two-week meeting aimed at making the Church’s teaching on family matters relevant to today’s Catholics.

Francis told bishops they shouldn’t even be afraid of showing him disrespect, saying he wants a frank and open debate that shouldn’t be reined in by fears that some issues are too taboo to even be discussed.

“You have to say what you feel the Lord tells you to say, without concerns of human respect and without fear,” Francis instructed the bishops at the start of their meeting.

At the same time, he urged the nearly 200 cardinals, bishops, and priests gathered for the synod to listen to one another with humility “and welcome with an open heart what our brothers say.”

The run-up to the meeting has been marked by mudslinging between conservative and progressive churchmen over issues such as whether Catholics who divorce and remarry without an annulment can receive Communion. Church teaching says such Catholics are living in sin and cannot receive the sacraments.

While insisting he is a “son of the Church,” Francis has said the Church must show more mercy and be a “field hospital” for wounded souls, suggesting he is seeking some sort of accommodation that conservatives say simply does not exist.

In a bid to encourage free-wheeling debate, the Vatican is restricting public information about what is said behind closed doors during the two-week meeting, not releasing texts of individual bishops as it has done in the past.

Francis set the stage for a wide-ranging debate when he decided last year to send a 39-point questionnaire to bishops’ conferences around the world, seeking input from ordinary Catholics about their acceptance of Church teaching on a host of issues related to Catholic family life.

The surveys confirmed that the vast majority of Catholics ignore and reject Church teaching on sex and contraception. The responses also said the Church must develop a pastoral plan to minister to gays in civil unions and to children being raised in such families, making the synod the first time the Vatican is addressing homosexuality on a pastoral level.

Church reform groups have said such honest responses, and the pope’s insistence that no issue is too taboo to be discussed, are reason for hope. Conservative groups, however, are hoping that the synod will reaffirm Church doctrine and make it more known and understood by Catholics.