Make a black one and double your sales by targeting guys as well as teen girls...
Black or grey would be a good color for teen guys.
To me, the iPhone 5c simply needs to outsell the iPhone 4S @ 16GB from last year in each quarter to be a success. Despite the iPhone 5 always outselling the iPhone 4S, the iPhone 4S still managed to be the second-best selling smartphone worldwide until the launch of the GS4. iPhone 5c should be far more popular come Christmas 2013 than iPhone 4S was last Christmas. Last year parents would have simply given their kids their hand-me-down iPhone 4S. This year their kids are going to want an iPhone 5c. However, to meet that Christmas demand, Apple should have done a darker color for boys. The blue one resonates well with males in the US, but I don't see the other colors being popular with males in the US.