During the AI-wars there were a lot of human casualties so the Army needed a lot of soldiers.

Before this war started, gene-technicians had already 'created life' in a petri dish, gestating humans as labour forces. Thus a whole new human race was created, which is since then known as In-Vitroes.

After the artificial fertilization in petri-dishes the embryo is put into an artificial gestation chamber (a tank) and those IVs are born when they reach the age of 18 years.

They are trained for duty in the military, in mines and other places in human society which are thought too dangerous for natural borns. During the AI-wars they had to fight instead of the usual human soldiers, but many didn't want to after many casualties among IV became known.

Because of gross malcalculation by the general staffs, natural born soldiers still had to fight in the AI-war and many of them died. Because of this, a new form of racism began. As of now the Invitros were called Tanks and were considered to be lazy and not patriotic enough.

In-Vitroes have a navel or omphalo at the back of their necks, immediately making them recognizable as In-Vitroes.

They are born and trained in IVA Facility Centres and are strictly kept away from natural born humans.

In the series we see apart from 1st Lieutenant Cooper Hawkes and Lieutenant-Colonel T. C. McQueen only four other InVitroes. One who assasinates General President Chartwell, and the crew of the engine room on the MacArthur from the episode Mutiny..