Arsene Wenger believes in youth and nowhere does he buck the conventional wisdom so much as in his defense. Whereas most other clubs believe in older defenders providing more stability, Wenger's defensive line's average age is 23 years. The youngest Johann Djorou is 19 years and the oldest William Gallas is 29 years. Contrast this with Man Utd's average age of 28+ years led by veteran Gary Neville, Chelsea's 27 years, and Liverpool's 27+ years. The club with the most porous defensive line is Charlton having given away 40 goals with an average age of 27 years. So far Wenger's boys have let in 19 goals which compares very favorably with Man Utd's 15, Chelsea's 17, and Liverpool's 16.
Wenger's derring do extends to the fact that these clubs have defenders in their squads who are barely 20 years or younger like Ryan Shawcross, Kieran Lee, Gabriel Paletta, and Miki but because Sir Alex Ferguson, Jose Mourinho, and Rafa Benitez are not exactly known for their risk taking, rarely get to see any playing minutes. Wenger's approach proves that young players can play good defense.
Wenger's penchant of encouraging young players to see first squad duty and to throw them in to meet head on with the big boys of the other clubs makes Arsenal the best club in the world for encouraging young talent.