Thanks for telling us about the work by Kendall. The first article can be found here:
I don’t have access to the second source (Kendall’s book). So I’m just basing this off the above article. It’s an interesting article that perhaps we should discuss in its own thread.
The close kinship of mankind especially in the same nation has an important bearing on one or two points of theology. Since mental and physical tendencies are transmissible by hereditary descent, this kinship gives to the doctrine of natural depravity an awful significance, and shows the causes of taint to our blood to be near us in time instead of being removed altogether away to the beginning of the world…
It is singular that orthodox theologians should overlook this recent pressing source of depravity to dwell on the influence upon us of an original pair living before historical times. It is equally strange that unorthodox ones should deny the existence of depravity communicated from that remote period on the ground of its supposed injustice, when it is undeniable that we are reached by ten thousand impure channels so near at hand.
Later, Kendall brings up the implication on the genealogy of Jesus:
This doctrine of the close kinship of mankind triumphantly establishes, apart from genealogical tables, the fact that Jesus Christ had descendants from King David, but impairs the value of the fact when it is established. David, the King of Israel, flourished above a thousand years before Christ, and left behind him many children. The channels of succession being so numerous, and having their fountain-head so far back, had time before the birth of Christ to branch out in every direction, and could not have missed any genuine Jew in the land, especially if he was of the tribe of Judah.
He also points out that we have kinship with Christ, due to genealogical ancestry:
The evidence seems conclusive that Mary, the mother of Jesus, had several children after the birth of her illustrious First-born. He had brethren and sisters, and if some of these left posterity in the earth, as we may reasonably suppose they did, it is certain that we are the descendants, the children, of Mary, and have a kinship with Christ, much closer physically than we have dared to believe.
In his case the phrase “Son of man” had a unique significance, but the doctrine which has been expounded in this paper shows that it has a real and solemn significance to whomsoever applied. Each of us is “son of man” in the tremendous sense that he is descended from all the people who have posterity remaining, who lived on earth a few centuries ago. Every individual living before Christ who has descendants at all has them in us. We are the offspring of the whole of humanity at that time. Every slave and every lord in the days of Julius Cæsar has contributed to our being, and, looking back to those times, each one may consider himself not the child of a thin, thread-like line of parentage, but child of the race, son of all mankind.
Finally, Kendall uses genealogical science to argue the invalidity of hereditary monarchy.
That is what I got from a quick skimming of the article. (I might come back to it later when I’m less in a hurry.) So yes, he does do the math in a general way, though not as detailed as Rohde.
