When angels came down and had relationships with human women, why did their children grow to be giants?

This question is based on a common misinterpretation of Genesis 6:1–4. The text says, “[T]he sons of God saw that the daughters of humans were beautiful; and they married any of them they chose” (Gen. 6:2). These unions produced the “Nephilim,” a supposed race of evil giants that corrupted the earth (Gen. 6:4).

While some may disagree, I believe it is more accurate to understand these verses as referring to the intermarriage of godly and ungodly humanity. First, we need to consider the passage in context. Genesis 4:17–24 describes the genealogy of the ungodly line of Cain, followed by the godly line of Seth in 4:25–5:32. In this context, the “sons of God” refer to Seth’s godly line and the “daughters of humans” to Cain’s ungodly line. These two groups intermarried and produced children called the Nephilim. Although some think these were a race of giants (because of the translation in the KJV), that probably isn’t true.

The Nephilim were powerful and influential men (Gen 6:4), but not necessarily good. The word “Nephilim” literally means “fallen ones.” The intermarriage of the godly with the ungodly produced corrupt children who were powerful and influential. They corrupted the whole world, leading to the judgment of the Flood.

Biblical support for the angels’ view is weak. Although “sons of God” can refer to angels, the phrase more often refers to humanity (Deut. 14:1; 32:5; Ps. 73:15; Isa. 43:6; Hos. 1:10; 11:1; Luke 3:38; 1 John 3:2, 10). Also, when the New Testament (2 Peter 2:4; Jude 6) speaks of angels leaving their proper place, it refers to their fall with Satan, not to cohabitation with women. Finally, the Lord Jesus taught that angels are not capable of marriage or sexual reproduction (Matt. 22:30).