There are only two families in the ages before the flood, the sons Of God and the daughters of men (Genesis 6:1-8). The descendants of Seth were the sons of God (Genesis 4:25; Genesis 5:3-32). There was only one other family (Genesis 4:9-23). Therefore, the daughters of men were descendants of Cain.

Of the Fall of the Sons of God who were Captivated by the ...
... Chapter 22."Of the Fall of the Sons of God Who Were Captivated by the Daughters
of Men, Whereby All, with the Exception of Eight Persons, Deservedly Perished ...
//christianbookshelf.org/augustine/city of god/chapter 22 of the fall of.htm

A Question About the Fallen Angels who are Said in Genesis to have ...
... II. Second Conference of Abbot Moses. Chapter XX. A question about the fallen angels
who are said in Genesis to have had intercourse with the daughters of men. ...
/.../cassian/the works of john cassian /chapter xx a question about.htm

Of the Reasons Assigned by the Apostle for Bidding Women to be ...
... men had begun to grow more numerous upon the earth, there were withal daughters
born them; but the sons of God, having descried the daughters of men, that they ...
/.../tertullian/on the veiling of virgins/chapter vii of the reasons assigned.htm

Fragment ii. When Men Multiplied on the Earth, the Angels of ...
... the daughters? When men multiplied on the earth, the angels of heaven
came together with the daughters of men. In some copies ...
/.../africanus/the writings of julius africanus/fragment ii when men multiplied.htm

Parental Duties Considered and Urged.
... Before the flood we read of "sons of God" who married "the daughters of men;"
a sad union which led to the universal degeneracy of mankind. ...
/.../sermon xxii parental duties considered.htm

Jordan Means "Their Going Down. " Spiritual Meanings and ...
... as it is written in the Book of Enoch"if any one cares to accept that book as
sacred"in the days when the sons of God came down to the daughters of men. ...
/.../origen/origens commentary on the gospel of john/25 jordan means their going.htm

Moreover, as to this Word which is Written in the Gospel...
... of lightning [1742] upon the earth, while others, [1743] harassed by the dragon,
sought their felicity in intercourse with the daughters of men, [1744] and ...
/.../32 moreover as to this.htm

Answer to the Foregoing Arguments.
... For indeed it is "on account of the angels" [8886] that he saith women must be veiled,
because on account of "the daughters of men" angels revolted from God. ...
/.../tertullian/on prayer/chapter xxii answer to the foregoing.htm

The Daughters of Jerusalem
... this so extraordinary that they have held these women to be Galileans; but Jesus
addressed them as "daughters of Jerusalem." The Galilean men who had ...
/.../stalker/the trial and death of jesus christ/chapter xi the daughters of.htm

For the King There were Three Great Perils: the People...
... far north, and that perfect and voluptuous contour found only in marble figures
of Venus, above the great purple sea, and, below it, in the daughters of men. ...
//christianbookshelf.org/bacheller/vergilius/chapter 16 for the king.htm