The Catholic Encyclopedia gives this as the requirements:
The requisite
conditions are enumerated as three:
eminens doctrina, insignis vitae sanctitas, Ecclesiae declaratio (i.e. eminent learning, a high degree of
sanctity, and proclamation by the
Church).
It also notes that they receive this title because:
the great advantage the whole
Church has derived from their
doctrine.
I see no reason why women cannot meet these conditions. And the three there are do meet it in a very great way (some greater than other Doctors). Likewise, especially in the case of St. Teresa and St. Therese, they were commanded by ecclesiastical authorities to write their doctrine.
If the Church has taken the interpretation GP is taking above of that Scripture, writings by women would never be allowed to be published and distributed, and yet quite the opposite has been done with the works of great women saints throughout history.
I have been privileged to read at least one work by each of the 33 Doctors of the Church (and more than one thing for many of them) and the three women deserve to be there as much as any of the others. The doctrines taught by them are especially necessary in our times which is why they have been proclaimed doctors now, in my opinion.
Sts. Catherine and Teresa show the proper response to immorality, discord and faithlessness in the Church. Sts. Teresa and Therese show the path to sanctity in all aspects of one’s life, something lost on modern man who has reduced religion to a matter of theory or private opinion and has banished from everyday life. St. Teresa’s teaching on prayer is probably the best of any Doctor. Likewise, these three women show forth the Church’s doctrine on true femininity, something modern women need to learn from.