A Dutchman who wanted to change his date of birth to boost dating prospects has lost his legal battle to do so.
Emile Ratelband, still aged 69, wanted to change his birth date by 20 years to avoid what he called discrimination.
"We live in a time when you can change your name and change your gender. Why can't I decide my own age?" he said.
But the court disagreed, highlighting that many rights in law are based on a person's age, and changing it at will could cause many problems.
There was no legal basis to make such a change, it said.
"Mr Ratelband is at liberty to feel 20 years younger than his real age and to act accordingly," the judges said, but changing his legal documents would have "undesirable legal and societal implications".
Mr Ratelband, who calls himself a "positivity trainer", made headlines around the world with his unusual request.
Ahead of the hearing, he made TV and other press appearances, saying he felt discriminated against in both employment and on the popular dating app Tinder - and said his doctors had told him he had the body of someone in their 40s.
"If I'm 49, then I can buy a new house, drive a different car. I can take up more work," he said. "When I'm on Tinder and it says I'm 69, I don't get an answer. When I'm 49, with the face I have, I will be in a luxurious position."
Alongside the widespread media attention, he was criticised by some for comparing his bid to the position of people in the transgender community.
In court, Mr Ratelband argued that the date on his birth certificate was a mistake - even though he was born on that day, 11 March 1949.
The court agreed with him that age is part of a person's identity. But unlike a person's gender or name, which Mr Ratelband sought to draw comparisons to, it had further complications.
"Rights and obligations are also attached to age... for example, the right to vote, the right to marry, the opportunity to drink alcohol and to drive a car," the court said.
It found that the possibility of declaring oneself younger could open the door to the opposite - becoming older.
In its judgement, the court said that granting the request would cause "all kinds of legal problems" by effectively erasing 20 years of events. It pondered what would happen to qualifications obtained in that time, or a driving licence issued, or a marriage solemnised.
It also said that while changes to the law to allow a person to change their gender took place following a global debate on such issues, no widespread advocacy for the change existed, except for Mr Ratelband's lone case.
If he felt discriminated against, the ruling said, there were other ways to resolve that under the law.