In an entry on “patristics” in The Oxford Dictionary of the Christian Church, a standard reference work of Christianity, the church fathers are described as those authors who “wrote between the end of the 1st cent.… and the close of the 8th cent.,” which comprises what is termed the “Patristic age.” These authors, this entry continues,

defended the Gospel against heresies and misunderstandings; they composed extensive commentaries on the Bible, explanatory, doctrinal, and practical, and published innumerable sermons, largely on the same subject; they exhibited the meaning and implications of the Creeds; they recorded past and current events in Church history; and they related the Christian faith to the best thought of their own age.

In another major reference work dealing with Christianity’s history and theology, Christianity: The Complete Guide, it is noted that while there is no official list of the Fathers, there are at least four characteristics that denote those meriting the title of church father: their orthodoxy of doctrine, their being accepted by the church as important links in the transmission of the Christian faith, their holiness of life, and their having lived between the end of the apostolic era (ca. 100) and the deaths of John of Damascus (ca. 655/675–ca. 749) in the East and Isidore of Seville (ca. 560–636) in the West.
Recent study of the Fathers, this article goes on to observe, has tended to broaden the category of church father to include some figures many in the ancient church viewed with suspicion—namely, figures like Tertullian and Origen (ca. 185–254). This article also notes that, owing to the rise of feminist historiography, scholarship of this era is now prepared also to talk about church mothers (“matristics”). There is no doubt that feminist concerns have highlighted the way in which much of church history has been taught from an exclusively male perspective. But the problem with this category of “matristics” is that there are very few women in the ancient church who can be studied in similar depth to the Fathers since they left little textual remains. In the chapters that follow, I briefly note the role played by Vibia Perpetua (d. 202) and Macrina (ca. 327–ca. 379), for example; but, though I wish we had more detail about these fascinating women, any examination of them is bound by significant textual limitations.

Haykin, M. A. G. (2011). Rediscovering the Church Fathers: Who They Were and How They Shaped the Church (pp. 16–17). Crossway.