In the Vatican I council, the council taught that three conditions must be met for an ex-cathedra infallible statement by the pope.
The pope must declare:
(1) in the exercise of his office as shepherd and teacher of all Christians
(2) in virtue of his supreme apostolic authority
(3) he defines a doctrine concerning faith or morals to be held by the whole church
In Ordinatio Sacerdotalis, JPII states:
Wherefore, in order that all doubt may be removed regarding a matter of great importance, a matter which pertains to the Church’s divine constitution itself, in virtue of my ministry of confirming the brethren (cf. 22:32) I declare that the Church has no authority whatsoever to confer priestly ordination on women and that this judgment is to be definitively held by all the Church’s faithful.
- He does not specifically state that he is excercising his office as shepherd and teacher of all Christians. This is implicitly stated, but must be explicit for infallibility.
Also, he affirms that he is confirming his bretheren, meaning the Bishops, and does not address this to the universal Church.
Again, while this is implicit that it is meant for the universal Church, he must specifically state so.
- He does not declare that he is promulgating a dogma in virtue of his supreme apostolic authority.
- He does explicitly define a doctrine concerning the faith as to be held by the whole Church.
So 1 and 2 are lacking. 3 is present. However, all 3 must be present for a dogma to be infallibly proclaimed ex-cathedra.