Here’s the story: Pope Francis appoints first woman to senior synod post. And here’s some more information.
Now a Synod is not an Ecumenical Council, and it cannot teach infallibly. The only way a Synod might teach under a type of infallibility is if the Pope decides during or in relation to a Synod (as, for example, in the final document after the Synod) to use Papal Infallibility. In an Ecumenical Council, the Bishops participate in infallibility as they are the successors to the Apostles, though the Pope’s agreement is absolutely needed for any teaching of an EC to be “of the Council” and to be infallible. Also, under the Ordinary Universal Magisterium (OUM), the Bishops participate in infallibility with the Pope.
Individually, and in groups of Bishops which either do not represent the body of Bishops or which are not teaching with the Pope, the Bishops teach non-infallibly under the authentic Magisterium of the Church. Such non-infallible teachings can sometimes accumulate, over time, to reach infallibility under the OUM.
Women cannot be priests in the Catholic Church, and Christ did not give His Church the authority to ordain women to the priesthood. Since a Bishop is a type of priest, and a Pope is a type of Bishop, a woman cannot be Bishop or Pope. Therefore, a woman cannot exercise the Magisterium, nor participate in any infallible teaching of the Magisterium.
Priests also do not exercise the Magisterium. Though the priests of a diocese assist their Bishop in teaching the faithful, they lack the authority to exercise the Magisterium, and can only teach what Popes and Bishops have taught; anything else is their theological opinion, and not a teaching of the Magisterium.
Allowing a woman to vote on whether or not a particular teaching text will be approved by a Synod gives that woman (those women) pretended authority of a Bishop. The same is true if any man who is not a Bishop is given voting rights in teaching documents in any Synod or Council. This is problematic. If more women are given this role, and a set of women voted such that their votes were decisive, the teaching could be said to be invalid. It would not be a teaching of that Synod. But if the teaching is approved by the Pope, it would be a teaching of the Pope and of a minority of voting Bishops.
Women cannot be Bishops and therefore they should not be given roles which pertain to unique charism of the episcopal degree of holy orders. Women should not be permitted to vote in Synods and especially in Ecumenical Councils. Bishops are the successors to the Apostles. They are Shepherds who represent Christ, distinct from the sheep. It is not fitting to give the sheep roles which are essential and unique to the roles of the Shepherds.
I disagree with the role also given to priests, deacons, and male religious to vote on the teaching documents of a Synod. Only Bishops are successors to the Apostles, and the Church is Apostolic. Recall what happened when Pope Paul VI asked a commission of theologians (all men, I think) to advise him on what to teach regarding contraception. The majority wanted to approve of contraception. These were mainly non-Bishops. The specific gift of the Holy Spirit to assist the Church in teaching through the Magisterium is only given to Bishops, not to male priests, nor to deacons, nor to men or women religious, nor to theologians.
Ronald L Conte Jr