http://www.ipa.min-cultura.pt/docs/eventos/lapedo/lvfaq_corr.html
It is must reading for anyone wanting to understand some of the bias' in
anthropology.
Concerning the legs of the child, Trinkaus and Zilhao write in this paper:
"8. Tattersall and Schwartz dismissed the body proportions of the Lagar
Velho child as "unreliable population discriminators in the late
Pleistocene", basing their statement on a direct mis-quote of the work of
T.W. Holliday. In point of fact, Holliday (22) and ET previously (23)
demonstrated complete separation of Neandertals and European early modern
humans in crural (tibia/femur) indices.
Not only do the tibia to femur length proportions of Lagar Velho 1 align it
with the Neandertals and separate from European early modern humans (the
only relevant comparative samples), but the relative degrees of shaft
robusticity of the tibia and the femur can only be explained as a result of
low crural index -- otherwise the child would have had a biomechanically
impossible gait in which the upper leg was being loaded by body weight less
than the lower leg. Given that these leg proportions do indeed separate the
Neandertals from European early modern humans, the tibiofemoral proportions
of Lagar Velho 1 can only indicate Neandertal morphological affinities."