One bishop has boycotted the meeting and another has stayed at home to deal with fallout from the scandal.
In a sign of the extraordinary pressure the church has come under from the scandal, Archbishop Charles Chaput of Philadelphia had called for the synod to be scrapped so the Vatican could concentrate on preparing another bishops' meeting on preventing sex abuse.
The Irish hierarchy is represented by the Archbishop of Armagh Eamon Martin, who is Primate of All Ireland, and the Bishop of Derry, Donal McKeown.
Pope Francis got emotional in greeting two bishops from China, present for their first time at a Synod, during the homily of a Mass in St Peter's Square Wednesday. Applause broke out as the pope noted their presence in his homily of the Mass, attended by tens of thousands of people.
The church is enmeshed in sexual abuse crises in countries including Chile, Germany, the United States and Australia.
As sex abuse scandals continue to buffet the Roman Catholic Church, Catholics in the USA are steadily losing confidence in Pope Francis's handling of the crisis, according to a new survey by the Pew Research Center.
¡Confirmado! WhatsApp y un cambio verdaderamente molesto para los usuarios
No obstante, la confianza de los usuarios en la aplicación quedará duramente dañada. La filosofía de WhatsApp cambió desde que Facebook la adquirió hace cuatro años.
In terms of standing up for traditional morals, 56 percent said the pope was doing an excellent or good job, down from 81 percent in the first Pew poll assessing Catholic opinion of Pope Francis in 2014, while those who say he is doing only a fair or poor job more than doubled from 15 percent to 36 percent.
He attacked clericalism, which he defined as a view that priests and bishops are the elite who exercise power but he branded as "the root of many evils in the Church".
The pontiff, in opening the Synod on young people, said "Let us not be suffocated by our sins". He expressed his confidence in the new generations that, he said, "are capable of prophesy and vision" and prayed that the Holy Spirit may grant synodal Fathers the grace of being anointed with the youthful "gift of dreaming and of hoping".
In a statement issued following their two-day quarterly meeting, this country's Catholic Bishops'acknowledged the anger and dismay experienced by many in response to reports from a number of countries over the summer concerning the criminal abuse of children and its cover-up.
Pope Francis delivers a message during his weekly general audience in St. Peter's Square, at the Vatican, on September 26, 2018.