Are you saying angels are not created beings ? I didn't think so .. What is the tallest giant mentioned in the Bible, the KJV that is ? Og the king's bed was over 13 ' so I figure he was about 9-10 ' , Goliath about 9' .. I've seen 7 footers with my own eyes .. I could sit here all day and question with ''what if's'' .. I'm not educated and read poorly on about a mid grade level probably .. I look for tie-ins and scripture proving scripture, not hunting for missing parts that don't fit in or value (jewish or other fables), we are to search the scriptures .. My focus is partly to know the mind of Christ concerning both the Old and New Testaments so I don't care much about consensus .. For some reason you need to think fallen angel are sons of God and they mated with human women , I see more evidence they all must receive permission from God to kill, steal and destroy and idolatry is asking for it . Satan seeks who he may destroy , not every person he comes across or we'd be all gone long ago , a good lesson is in Job about it where Satan acts only with permission and imo is not sovereign any at all .. Do you get the picture why fallen angels mating with women is so out of the question ridiculous to me .. And why would I spend time on chasing such foolishness that leads to nowhere ? Except to give readers and non-believers answers from a point of biblical view that all fits together .. David's mighty men, could they not be considered as godly men of renown, fierce and even giant, even King David , giant in all but stature . Samson ?
Concerning ancient men being older when having sons and daughter ? I believe DNA loses information but never evolves to add information and certainly no evolution of kinds to other kinds .. So other than dramatic changes to earths environment pre-flood to post-flood that may have had impact on longevity , I don't know .. At some point God said a man is given 70 yrs , 80 if you're strong and after that his days are filled with trouble .. That means what it says .. We tend to think in parliamentary procedural terms to keep thing in order , God does not need it, He's God and He never changes , perfect, reliable and true to His every Word and way .. Amen .