The Heavy Gear RPG series has Earth's forces using the
GRELs (Genetically Recombined Experimental Legionnaires) who were developed from eugenics programs during WW3. The GRELs serve as shock troops and have a number of different models, with several designed for specific roles within the Terran military. Maxwell series GRELs act as gunners, for example, while Isaacs serve as field technicians and Minervas are pilots. While most of the GREL subtypes are competent within their respective niches, their status as "proper" people isn't universally respected by either the Terran Colonial Expedition Force or the inhabitants of the Terra Nova system. Some regard the GRELs as either inherently inferior or a potential threat because they might replace traditional soldiers, while others are more enlightened and tend to judge them as they would any normal individual on their own merits.
The New Earth Commonwealth has been secretly working on a next-generation program for SLEDGE soldiers, who ideally would be more refined than the standard types of GRELs and would also have the advantage of appearing like normal humans without some of the oddball quirks that are known to affect each GREL type. Isaac type GRELs are very good at their role in repair and maintenance, but many of them develop an uncontrollable urge to tinker with any nearby technology if they have nothing to do. But presently the SLEDGE project is still only in prototype form and highly classified.