Christina Aguilera rose to prominence in the 1990s as a child actress on The Disney Channel alongside Britney Spears, and later leveraged her likability and good looks to embark on a successful pop music career.  The similarities between her and many other teen divas of that era pretty well end there, though, because Aguilera can flat-out sing.  Her vocals are crisp and powerful in all three registers, and that ability is reflected in her wide-ranging, deceptively difficult catalog.  As Aguilera has matured both vocally and personally, she's been taking on more complex, weighty material.

Through the first six season, no Idol has turned in a 4-star performance of an Aguilera song, much less 5-stars.  And, as you'll note in the Performance table below, it's not as though no top-tier female contestants have tried.