Matthew 1:1 is called "The Book of the Generation" - Everything in Matthew refers to this same Generation.
Similar terminology can be seen in Genesis 5:1 " This is the book of the generations of Adam. When God created man, he made him in the likeness of God." All of the Descendants mentioned in Genesis 5 cover a time period of 1656 Years.
Another example of this type of Generation, reference can be seen in Genesis 37 "v.2 These are the generations of Jacob."
With Jesus, the meaning of Generation(s) changes drastically though.. The Generation, is no longer Flesh & Blood, rather it is a New Creation.. All that receive Jesus, and receive Baptism by Holy Spirit encompass This Generation.
John 1:13 " who were born, not of blood nor of the will of the flesh nor of the will of man, but of God."
The Generation is comprised of Sons of God, and is mentioned in Generation 3:15, in addition to the Righteous, there is another Generation / Seed.
The other Generation mentioned in 3:15 is Mentioned at Mark 8:12 " And he sighed deeply in his spirit and said, “Why does this generation seek a sign? Truly, I say to you, no sign will be given to this generation.” (Matthew 12:39,Luke 11:29)
When Jesus says " Truly I tell you, this generation will certainly not pass away until all these things have happened." Matthew 24:34. He is not pointing to a time Period starting in 1914, rather he is re emphasizing what He says in Matthew 24:21 " if those days had not been cut short, no human being would be saved. But for the sake of the elect those days will be cut short. "
"This Generation" is all Spirit Annointed Christians, on earth up until the time of the Great Tribulation. Thoughts / Other Perspectives?