In Rufus Wainwright's case, it's easy. Son of folk singer Loudon Wainwright III, much-vaunted as the next Bob Dylan, and Kate McGarrigle of the McGarrigle sisters, Wainwright couldn't be more different from his parents - though he is sure to enjoy equal success.
In these days of ostentatious technical wizardry, there's nothing more dramatic than the sight of a man in a flimsy T-shirt and jeans seated at a grand piano in front of a sea of lamp-lit tables. "I feel like I'm in the Moulin Rouge," announced Wainwright, taking in the backdrop of red velvet and twinkling lights. The scene before us perfectly reflected the old-fashioned simplicity of Wainwright's debut album. Even with its lyrical beauty and black humour, the most extraordinary thing about the record is that it was made in this decade. The 26-year-old singer-songwriter owes more to the show-tune traditions of Gershwin and Gilbert and Sullivan than the folk of his parents. During "Foolish Love", an eerie elegy about the short-lived nature of love that is seamlessly transformed into a thigh- slapping show tune halfway through, you half expected a line of dancing sailors to appear from behind the curtains.
A sense of urgency underpinned Wainwright's crooning, as he imbued each word with an almost overwrought intensity. His most tragic moments echoed the visceral tones of Jeff Buckley, but rounded off with a winning Judy Garland trill. And despite his years, his songs were brimful of adolescent melodrama. When he wasn't fantasising about glamorous ways of dying, he was offering us his wounded heart to be examined and admired.
The uncompromising old-fashionedness of Wainwright's sound was reinforced by melodramatic piano arrangements which evoked a host of matinee idol clinches, though the cabaret-style melodies and barbed lyrics call to mind something considerably more sleazy. Buried in the cotton-wool balladry of "In My Arms", came the line "Wish you were here to chain you up without shame", delivered by Wainwright with a mischievously raised eyebrow.
Some songs sorely missed the louche glamour of his recorded material, mostly due to the absence of a string section, but Wainwright managed to keep things moving by sporadically picking up a guitar and bringing on guest singers.
The audience seemed to draw a collective breath as he brought on his mother to join him in some harmonies. Her voice was weak next to her son's, but it was a touching sight none the less. It seemed Wainwright's music was not the only thing at odds with his contemporaries. This guy loved his mother as well.