The quickstart races seem to be the same each time they are selected. If you save the empire and and load it for a new game though, there is a bug in which you get lots of extra research points.
Captain Kwok said:
The 14 main races always use the same traits and stuff as defined in their setup files. Only neutrals have randomally generated attributes etc.
I suspect even these are governed by the Default_Setup_Script file, in that if you add a new one but it isn't listed in the Racial Traits section of that, they won't choose it.