How many ‘greats’ go before ‘grandfather’ between Adam and me?

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Whilst it is impossible to give an accurate figure, this is an interesting question and most people are quite surprised by the estimated answer. We all seem to grow up with the notion that human history is very, very long and our earliest ancestors are so remote from us that there must be hundreds, if not thousands, of generations between us and them. This is certainly the impression given by the teaching of evolution, but we should remember that Charles Lyell designed his long time-scales in geological history specifically to undermine the reliable record in the Bible. Given that the question concerns the first man Adam, this answer works within the Biblical account of earth history stretching back in time somewhere between six and seven thousand years.

For ease we will consider the generations between Adam and ourselves in three sections. These are from Adam to Abraham, from Abraham to Jesus Christ, and from the time of Christ to today. The number of generations in the first two sections are easy to work out for those with confidence in the record of the Scriptures. This is because the Bible details the lineage of Christ all the way back to Adam. The main purpose of these records is to demonstrate that Christ was indeed a Son of Adam, who could therefore legally settle the debt first incurred by Adam. We should remember that this is the primary purpose of these genealogical records, and the fact that they enable us to make a rough calculation of the date of creation is a secondary benefit. But if the record have legal standing for the purposes of tracing descent, they must also be reliable for that purpose too,

Abraham was born approximately 2000 years after Adam’s creation. This period is covered in just 20 generations, including both Adam and Abraham. There are two reasons for this. The first is that prior to the Flood and for some time afterwards, human life-spans were longer than we consider ‘normal’ today. Secondly, this longevity enabled people to have children when they were much older than we are used to. In this period the youngest father listed is Nahor, Abraham’s grandfather, at 29. The oldest is Noah at 502. The average age for the father when the listed son was born is just over 100 – unthinkable today, but that is a measure of how much we have been affected by the consequences of sin. The data for these generations is in Genesis 5 & 11, or in 1 Chronicles 1-3 given as a single list without ages but with brothers and cousins interspersed.

Many more generations featured in the next 2000 years, but they are documented carefully because of the need to trace Christ’s ancestry. Genesis only takes its records to Jacob (Israel) whilst 1 Chronicles provides His lineage through to the time of the Babylonian exile. It is in these three chapters and in Ruth 4, that the Old Testament traces Messianic descent through to King David, who was born about 1000 years before Christ. Chronicles traces some of David’s descendants through Solomon through to Hodaviah, one of the seven sons of Elioenai. These two men are not listed in either of the New Testament ancestries of Jesus, but their ancestor Zerubbabel appears in both Matthew’s and Luke’s records. The two lists in these gospels are very different and it is generally accepted that this is because Matthew traces Christ’s lineage through Joseph His ‘adoptive’ father, whilst Luke looks at His blood line through Mary, even though he does not mention her by name. There are differences between some of the Biblical lists which we do not have the space to discuss here, but it is right to acknowledge that Luke’s lists seem to include two copyist errors, Cainan before the Flood and Arni between Abraham and David, because these men are not listed elsewhere. Matthew also omits three kings who may have been excluded from the official records because of the evils of their father, with Exodus 20:4-5 being the passage usually quoted in this regard.

Of more significance to the question we are addressing is that allowing for the adjustments above, Luke lists 74 generations through Mary after Adam whilst Matthew has 63 through Joseph (adding his record from Abraham to the 20 previous generations). This difference is not a problem if we consider the realities of births within a family line. There can be no exact figure for a generation, as it is the time between each parent’s own birth and them having a child. Most modern Western families have a small number of children over a brief period of time. However, even in our societies it is not completely unknown for someone to have an aunt or uncle who is younger than they. In such cases two lines in the same family can easily get out of sync with each other. Our own youngest child is just 5 years older than our oldest grandchild – it is easy to see that they could have their own children at about the same time in the future. The Biblical record therefore says that from Adam to Christ through Mary required 75 generations including both men. In Matthew’s list there are just 64 names, tracing His ancestry through Joseph.

There are no public records easily available for the final 2000 years, so we need to estimate the number of generations in some way. If we take Luke’s record for the period from Solomon, David’s son, to Christ we have an average “generation gap” of 23.5 years. Over the same period, Matthew returns one of approximately 31 years. These give us a minimum of additional generations of 65 and a maximum of 86 in the last 2000 years. We could of course suggest an average generation gap slightly different from these two limits, but on what criteria might we base this? Remember we are working with the average age for child birth. Social, political and environmental conditions have varied so much in the last two millennia, and all these affect lifespans and birth rates, so the above figures seem as reasonable parameters as any for our calculations.

We do however have access to one family record to shed further light on this question. Some years ago one of Creation Research’s supporters, Joel Black, emailed to them to say, “I have Jewish ancestry, and if the record they have compiled of the family is correct, there are precisely 139 generations from Adam to me. Thus Adam would have 136 greats to me.” How does this correlate with my estimation above? The least possible number of generations would be 20+44+65=129 and by comparison the greatest would be 20+55+86=161. Even then we should allow further tolerance, so our best estimate has to be between 120 and 170, into which the Black family records easily fit. As Joel pointed out when asking, “How many greats would you need to put before grandfather to get back to Adam?” you need to subtract three from the total - one for yourself, one for your father and one for your grandfather.

As we consider that each of us is on average about 145 generations from Adam, we must not lose sight of an even more important point. What each one of us inherits without trying from our greatest-great-grandfather is sin and death. We all have sinned because we are his natural descendants. Paul explained further in Rom. 7 that we also still struggle with sin, “For the good that I will to do, I do not do; but the bad I will not to do, that I practice.” Frustrated, he cries out, “O wretched man that I am! Who will deliver me from this body of death?” Earlier in this same letter Paul had explained the seriousness of this problem. Looking back to Adam he said “through one man sin entered the world, and death through sin, and thus death spread to all men, because all sinned”.

Thankfully Paul knew the solution to this inherited problem; “For if by the one man’s offence many died, much more the grace of God and the gift by the grace of the one Man, Jesus Christ, abounded to many.” And “For as by one man’s disobedience many were made sinners, so also by one Man’s obedience many will be made righteous.” (Rom. 5:6-21) Christ of course has no physical descendants, so we cannot inherit His righteousness through human descent - yet He spoke of His disciples “inheriting eternal life”. Throughout the New Testament there are many references to Christians having an inheritance and in Titus 3:7 we are described as “heirs according to the hope of eternal life”. Again in Romans Paul explained at length that it was Abraham’s faith which was accounted to him as righteousness by God. In fact he built much of his argument in this letter on the promises first given through the prophet Habakkuk, “The just shall live by faith.” If we have faith in someone in authority, we trust them enough to do what they ask. Jesus showed His faith in His Father by doing His will in all things. We can become His heirs through faith if we are prepared to trust and obey Him. When we are adopted as our Creator’s heirs, the good news is that He has no grandchildren nor great-grandchildren. There is no need to count back how many generations are between us and Him; in Christ we are all His Father’s first generation sons! Unlike our inheritance in Adam which is impossible to avoid, our righteousness in Christ is provided through a serious appeal for salvation from us to Him.

This paper was first published on Creation Research’s Ask John Mackay website.
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