The only clue was a Florida address scribbled down in 1946 by his German mother who had sought solace in the arms of an American GI in the chaotic aftermath of the Second World War.

As a young man he wrote to the address but never received a reply. Then his own advancing years - he is now in his 60s - and a severe illness spurred him into action again.

He studied US Army campaign maps to find out which units had been in the area and last year, he finally had enough information to present his data to a search agency.

It found his father had died in the US in 2001 without knowing he had another son, but there was a silver lining. Hones found his half-brother and they now write to each other with his daughter - now in possession of a new American uncle and family - doing the translation.

Hones has become one of the thousands of Germans racing against time to track down their real fathers, or in some cases grandfathers, and their other families in the US, Britain and Russia.

Called the Soldatenkinder, they were the product of relationships between Allied soldiers and German women when the country was occupied after 1945. For a generation, being Soldatenkinder was a source of shame. But many of the children now want to find their own roots albeit often using only the sketchiest of details.

Analysts say the search is being given added impetus by new technology and the fact that having a foreign soldier for a father no longer carries the stigma it once did.

Between 1945 and the formal end of Allied occupation in May 1955 an estimated 100,000 children were born to German mothers and Allied soldiers.

Many of the servicemen, fearing punishment for breaking non-fraternisation rules, did not keep the relationships going, while the mothers were often ashamed of having been involved with the enemy.

According to Families International, a Frankfurt-based search agency, easier international communications, the possibility of DNA testing, and changing attitudes has led to a surge of interest

"This is a phenomenon which has been growing markedly in recent years," said spokeswoman Sabine Benisch. "Last year, we had about 120 cases of this kind, and that would be about 50% to 60% more than maybe a decade ago.

The whole stigma about having a foreign father has gone. At that time, a woman who found herself pregnant to a foreign soldier would have been ashamed and might have just got herself married as quickly as possible to avoid a scandal."

Heinrich Rehberg, head of the personal search department for the German Red Cross, said: "There are a great number who are now beginning the search. We are receiving new requests almost daily.

"Many began trying to search in their youth and came up against a brick wall. Now that they have sorted out other things in their lives, they are starting again."

A typical search can take anything between four weeks and two-and-a-half years. Millions of Allied soldiers spent time in Germany during the latter stages of the war and during the Occupation. Exotic British, American, French, or Russian names and addresses could be mis-spelled and only half-remembered.

Susanna Panter, the founder and director of the search and contact agency Wiedersehen macht Freude (Meeting Again Makes Happiness), said: "It can be very difficult. You might have elderly people basing their search on information they heard many years ago from someone who knew little English.

It could be confusing which was the first name and which was the surname. And when they told the names to their children there was another chance that details could be confused.

"At the time, people were too busy working to survive to spend any time researching their roots. But now they feel that they have sorted their own lives, and those of their children, and can now spend time on it."

In the immediate post-war period, many women gave their soldiers' children up for adoption, especially if the father had been black. The US even organised a "brown baby programme" to have the children of Afro-American soldiers "returned" to the US.

Despite the stigma, some children of Allied troops became national figures. One of the most prominent is the former Bayern Munich coach Felix Magath, born to a Puerto Rican father in 1952. Magath has only been in close contact with his father since 1999.