Who are the giants described in Genesis 6? Did the sons of Adam and Eve have intercourse with their sisters?
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.
Using Strong’s Concordance: Giants 05303 Hebrew: Nephilim Translated in the King James Version – ‘giant’ 3 times.From Wikipedia:Giantism, is a condition characterized by excessive growth and height significantly above average. In humans, this condition is caused by over-production of growth hormone in childhood, resulting in people 2.1 to 2.7 m (7.0 to 9 ft) in height.It is a rare disorder resulting from increased levels of growth hormone before the fusion of the growth plate which usually occurs at some point soon after puberty. This increase is most often due to abnormal tumor growths on the pituitary gland.
From this we understand that this anomaly amongst human beings (which is still occasionally seen today) was present right at the beginning. None of these original giants survived the flood.
We notice that giants were in addition to, not a result of, the sons of God taking wives of the daughters of men.
We are not to suppose that the ‘sons of God’ here refers to angels, because angels do not marry or reproduce. All angels do God’s will perfectly. Equality with the angels is the reward promised to the faithful in the kingdom of God.Luke 20:34-36
The ‘sons of God’ refers to those like Seth who called upon the name of God. Genesis 4:26; Romans 8:14
The daughters 'of men’ refers to the female progeny of the line of Cain who refused to serve God.
The children of these unions became ‘mighty men’ of ‘renown’ – despots in other words, the kind of men we are all too familiar with today.
Adam is the father, and Eve is the mother of all living. Genesis 3:20
It therefore follows that the male descendants of Adam and Eve would have had no choice but to marry the female descendants of Adam and Eve i.e. their sisters or cousins.
At the beginning, children born of close family relationships did not present the problems that it does today.
This because God’s instruction to Adam and Eve was to have children and populate the earth. Genesis 1:28
A similar thing happened at the time of the flood. The people alive today are all descendants of the three sons of Noah and their wives. Genesis 9:1
I hope you find this helpful.