I have ran an analysis similar to the analysis listed http://surfer.nmr.mgh.harvard.edu/fswiki/Fsgdf4G1V.  I get a results that was quite different from group analysis controlled for age compared to group difference controlled for both gender and sex. I have similar picture analyzed with a previous version of Freesurfer 4.30 that has different part of the brain highlighted. I get quite similar results for the group analysis when comparing Freesurfer 4.30 and Freesurfer 5.1.

Knut J