He has two legitimate birth certificates. One indicates that he was born in 1920, and the other shows 1923. Because of the records from back then, either of them could be right, so he is going with the 1923 one for now.
What if you had two birth certificates? Which one would you choose to be the “right one”? Would you want the “older” one or the “younger” one?
The reality is that, if you are a Christian, you do have two “birth” certificates. Both mark a “date of birth.” One is a legal record of your entry into this world. The other one, which is infinitely more important, is a heavenly record of your entry into Christ. The first was written by a clerk on a piece of paper; the second was written by God in the Book of Life. One is needed to secure a Passport for passage to and from other countries; the other is needed to secure passage into heaven itself. Thank God for our citizenship (by birth, John 3:5) in heaven (Phil. 3:20)!