An MP wants passport rule changes after a constituent was denied one because he has lost touch with his mother.
Gary Evans has his passport pictures ready and waiting
Clwyd West Conservative MP David Jones has taken up the case of Gary Evans, 22, from Kinmel Bay in Conwy.
Mr Evans said the Passport Agency wanted details only his mother could give, but they lost touch 20 years ago.
The Home Office Identity and Passport Service said it would be sympathetic to anyone who proved they had done everything to get the information.
But the MP said fathers should be able to vouch for their children's nationality.
Mr Evans, a former soldier, has already travelled abroad on a military passport.
But to obtain a civilian one, he said the Passport Agency wanted either his mother's passport number, her birth certificate or a Home Office certificate of registration or naturalisation for her.
He said his parents were never married, and they split up when he was a toddler.
He lived with his father, and neither has had any contact with his mother, Denise Jones, since then.
MP David Jones has written to the Home Office
Mr Evans said obtaining a copy of his mother's birth certificate was impossible, because he does not even know her date of birth.
An alternative would be to provide his father's wedding certificate, but they never married.
Mr Evans said: "I was good enough to swear allegiance to my country as a soldier, but now they won't give me a British passport.
"We have all booked a family holiday to the Dominican Republic at the end of this month and I've discovered I can't get a passport.
"It's ridiculous. The government doesn't know what on earth it's doing.
"We have done everything humanly possible, but we just can't find my mum's date of birth."
Mr Evans' father, Tony, claims the Home Office told him he can get round the problem by legally adopting Gary and his brother.
He said: "It's absolutely ridiculous - being told to adopt my own sons. They're both in their 20s.
"If that wasn't possible, the Home Office told me my sons could apply for British citizenship - and that can take up to three years."
He added: "It's just ludicrous. We don't know where to turn or what to do."
Mr Evans' MP David Jones claimed the rules were unfair to single fathers and he has written to Home Office minister Tony McNulty.
He said: "Whilst it was historically easier for a mother to prove parentage, there seems to be no good reason today why a single father should not be allowed to prove parentage by, for example, a DNA test supported by a statutory declaration."
A spokesman for the Home Office's Identity and Passport Service said it would look "sympathetically" on anyone who proved they had done everything in their power to obtain the necessary information.
But he added: "We don't make any apologies that it is not easy to get a passport.
"We have got to be able to prove that someone is British before we can get them a British passport. It's essential we have a robust system."