Genesis 6:1

And it came to pass, when men began to multiply upon the
face of the earth
Either mankind in general, or rather the posterity of Cain, who were mere natural men, such as they were when born into the world, and as brought up in it, destitute of the grace of God, and of the knowledge and fear of him; and who in proportion much more multiplied than the posterity of Seth, because of the practice of polygamy, which by the example of Lamech, one of that race, might prevail among them: and daughters were born unto them;
not daughters only, but sons also, though it may be more daughters than sons, or it may denote remarkable ones, for their beauty or immodesty, or both; and chiefly this is observed for the sake of what follows.