Gen is conformed to M4, it does not seem parented to any particular part (when viewing the hierarchy).  I would say, however, given the physical appearance, that it is parented to the hips.  Where else?

I believe that the problem is simply that many morphs which expand the torso were left out of the M4 Gens when it was created, and I simply lack the programming skills to insert them.

Klebnor

Lotus 123 ~ S-Render ~ OS/2 WARP ~ IBM 8088 / 4.77 Mhz ~ Hercules Ultima graphics, Hitachi 10 MB HDD, 64K RAM, 12 in diagonal CRT Monitor (16 colors / 60 Hz refresh rate), 240 Watt PS, Dual 1.44 MB Floppies, 2 button mouse input device.  Beige horizontal case.  I don't display my unit.