The sons of God saw that the daughters of humans were beautiful, and they married any of them they chose.
Genesis 6:2 (NIV)
Translators do violence to the text.
This word we translated as "beautiful" here? FIFTEEN TIMES this Hebrew word is used before this, and EVERY SINGLE TIME, the word is "GOOD."
"Good" is how God described the world he created in Genesis 1. It's the same "good" of the Tree of good and evil knowledge.
The theological paths you can take here are absolutely tremendous.
The daughters of humanity were GOOD. What does this teach us about women? What does it say about God's view of them? Who or what corrupts them by way of violence?
There is much water to draw from this well.
Another important link:
When Sarai is taken by Pharaoh in Genesis 12, she is described as beautiful (yawfeh), but when Esther is taken by Xerxes in Esther 2:7, she is described as both good (tov) and beautiful (yawfeh). And actually, the whole book of Esther links Haman with the concept of “falling,” which is the same root word as the Nephilim in Genesis 6. One might argue that Haman is Nephilim, and both the Pharaoh and King Xerxes are like "sons of God" who take women they please.