Emile Ratelband, who is - for now - 69 years old, told a Dutch court this week he didn't feel "comfortable" with his date of birth and wished to have it change from March 11, 1949, to March 11, 1969.
The pensioner wants to be recognised as being 20 years younger than his actual age.
Ratelband said that according to his doctors he has the body of a 45-year-old, and described himself as a "young god".
His local authorities have unsurprisingly refused to change his legal age in response to his request, and Ratelband has filed a lawsuit; he has several arguments to back up his demand.
A court in Arnhem, in the eastern Dutch province of Gelderland, is expected to deliver its decision on Ratelband's age within four weeks.
He explained: "I have done a check-up and what does it show?"
Ratelband's website also says his "age focus is to turn at least 94 years old and to then leave this world healthy and with pleasure when it has become a better place for everyone". "If I'm 49, then I can buy a new house, drive a different auto", he said.
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"When I'm 69, I am limited". If I'm 49, then I can buy a new house, drive a different vehicle.
Ratelband reasons that he lives in a society where people can change their genders, so, to him, it only makes sense that he can change his age.
He said employers are reluctant to hire someone as old as a pensioner as a consultant.
The judge expressed some skepticism but also noted that changing the sex on a birth certificate, as transgender people have the right to do, once was impossible and is now allowed.
'For whom did your parents care in those years?
Dutch newspaper Algemeen Dagblad reported the court was sceptical of the suit, saying there was no legal mechanism allowing a person to change their birth date.
But Mr Ratelband does not want to receive a pension yet, and he has pledged not to claim for one until he reaches retirement age again should he win the case.