The Bible is very clear that angels do not procreate.
Jesus' answer to the Sadducees trick question re the resurrection recounted in Mt22:23-30 provides the most direct answer to this question.
The sons of God is simply a reference to believers obedient to God, likely the descendants of Seth, and the daughters of men, those who were disobedient unbelievers or pagans likely the descendants of Cain.
There's a reason the 'Book of Enoch' (or 'books' - which one are we discussing?) is not included in the Bible - -because it contradicts clear doctrine of the Bible taken as a whole.
"Come now, and let us reason together, saith the Lord" Is1:18;
There are some good Biblically well grounded studies on this question easy to find.
