Gait and Posture have published a recent study regarding lower limb rotation in children.  Over one thousand healthy children were clinically evaluated.  The following results were found:

1.  There was a significant difference in femoral anteversion between males and females with females having increased femoral anteversion that correlated with age

2.   There was no difference between the right and left sides of femoral anteversion

3.  There was no significant difference between males and females for tibial torsion. 

4.  There was no significant difference between the right and left side for tibial torsion.

Reference:  Michel Jacquemier, Yann Glard, Vincent Pomero, Elke Viehweger, Jean-Luc Jouve and Gérard Bollini (2008) Rotational profile of the lower limb in 1319 healthy children.  Gait and Posture 28(2): 187-193.  Retreived on 8/5/08 from doi:10.1016/j.gaitpost.2007.11.011