BERLIN — A gay Afghan 18-year-old who was seeking asylum in Austria because he feared persecution in his country had his application denied because the authorities said he did not act like a stereotypical gay man, citing his walk, behavior and clothing, according to a Vienna-based organization that helps refugees.

In a case that illustrates the plight of many L.G.B.T. refugees coming to Europe, the organization, Queer Base, said the teenager, whom it did not identify, provided testimony at an asylum hearing this spring that he became aware of his sexuality when he was 12 and living in Afghanistan.

He migrated to Austria as a minor, according to the organization, which kept all other details of the teenager’s life and journey confidential at his request.

But after he applied for asylum, the document outlining the decision quoted an official as saying that the man’s claim that he was gay was not believable based on how he had acted while living in Austria.