Supported by developments in other Christian Churches
The Second Vatican Council teaches that the Catholic Church must learn from other Christian Churches
“All who have been justified by faith in baptism are incorporated into Christ. They are rightly called Christians. With good reason they are accepted as brothers and sisters by the children of the Catholic Church.” (Ecumenism § 3)
“Many of the most significant elements and gifts which together go to build up and give life to the Church itself, can exist outside the Catholic Church.” (Ecumenism § 3)
“Christ summons the Church, as she walks her pilgrim way, to continual reformation, a reformation of which she always has need.” (Ecumenism § 5)
In other Christian Churches women are now being given access to all the ordained ministries.It applies not only to evangelical churches, but to some mainstream churches close to Catholic tradition, such as the Old Catholics, the Methodists, the Anglicans & Episcopalians. See examples here.
Admitting women to the ministries is the outcome of a long process of prayer and study by our Christian brothers and sisters. Their truly Christian motivation and their genuine search for establishing what Jesus really wanted can be read in the publication of many classic works.
The example of the other Christian Churches does not prove the correctness of ordaining women in an absolute fashion. But it is a serious indication that this is the path the Holy Spirit urges also on the Catholic Church.