I was reading about where Cain got his wife (Genesis 4) and read this statement: “If we assume that Adam and Eve gave birth to other sons and daughters (one per year starting at 20 years of age), who had sons and daughters and so on, there could have been at least ten thousand people by the time Adam was 130 years old.” I am really curious about how you got to the number of 10,000. I am not trying to refute it or say that's too big. I just really want to know the math behind that statement. How was that worked out to equal 10,000?
To estimate the world’s population is never easy, but to do so back when Adam was 130 years old, might at first thought seem very difficult. The calculation can be performed by assuming that Adam and Eve started having children immediately after God commanded them to be fruitful and multiply (Gen. 1:28). Adam and Eve were mature adults who could have children. If we assume that they gave birth to a child every other year, they would have given birth to 65 children by the time they were 130 years of age.
If we assume that their children do not start marrying each other until they are about twenty years of age, then the first two children who marry could have given birth to about 56 grandchildren by the time Adam and Eve were 130 years of age. The second two children who marry could have given birth to about 55 grandchildren. The next two children who marry could have given birth to about 55 grandchildren also. If we continue counting we discover that Adam and Eve’s children could have given birth to 1,536 grandchildren by the time Adam and Eve were 130 years of age.
Next, we must do the same for the grandchildren’s children. If we do the math, we discover that the first set of grandchildren could have had 45 great grandchildren. The next two grandchildren from the first set of parents could have 44 great grandchildren. If we continue counting we discover that the first set of 1,536 grandsons or granddaughters or 768 couples could have given birth to over 10,000 children all by themselves.
If we continued the process we discover that 10,000 children is a very conservative estimate by the time Adam and Eve are 130 years of age.
Those who criticize the Bible usually do so without all of the facts, because they usually do not care about facts. They only want to criticize. Many who criticize the Bible have never read the entire Bible. May God bless you for seeking to discover the truth and understand.
Suggested Links:Where did Cain's wife come from?
Peace With God