John 10:10, good points. You will also find, if you check, that the plagues had, in many cases, a natural connection. I did a rather long study on this a couple of years ago and will see if I can condense it on a thread sometime after this week is finished!
I AM FREE, no, you have it wrong with that connection. Genesis 6:4 states that the Nephilim were "on the earth in those days -- and also afterward -- when the sons of God went to the daughters of men and had children by them".
First of all, it is stated that the Nephilim were there at the same time, not that they were the progeny of the forbidden marriages.
Secondly, the sons of God are believers. It is forbidden all the way through the Bible for believers to marry unbelievers. It was no different in antediluvian times, for God does not change.
These were not 'angelic/human' unions. There is a basic genetic problem there!