ANSWER: No they did not. The Scriptures reveal that angels are created spirits (Hebrews 1:14). They are not mortal flesh and blood human beings, and do not reproduce sexually or by any other means. Jesus told the Sadducees: "...The sons of this age marry and are given in marriage, but those who are counted worthy to attain that age, and the resurrection from the dead, neither marry nor are given in marriage; nor can they die anymore, for they are equal to the angels and are the sons of God, being sons of the resurrection" (Luke 20:34-36). Also see Matthew 22:30 and Mark 12:25.
Who then are the "sons of God" described in Genesis 6:4? "There were giants on the earth in those days, and also afterward, when the sons of God came in to the daughters of men and they bore children to them. Those were the mighty men who were of old, men of renown." The "sons of God" were male human beings. Notice that Adam was a "son of God" by creation in Luke 3:38. By extension, all of Adams male descendants are by God's act of creation "sons of God."
The entire context of Genesis 6 concerns human beings not angels. Notice the following verses in particular: Genesis 6:3 "And the LORD said, 'My Spirit shall not strive with man forever, for he is indeed flesh..." and, Genesis 6:5-7 "Then the LORD saw that the wickedness of man was great in the earth, and that every intent of the thoughts of his heart was only evil continually. And the LORD was sorry that He had made man on the earth, and He was grieved in His heart. So, the LORD said, 'I will destroy man who I have created from the face of the earth, both man and beast, creeping thing and birds of the air, for I am sorry that I have made them.'" God had determined to destroy sinful man except for Noah and those who were with him on the ark (Genesis 7:21-23). Angels cannot be destroyed by drowning. The angels time of judgment is yet to come (Jude 6).