[@my Lalia]
Good Question. Well here is a short list that will help.

[b]Approved Races[/b]
[list]
[*] Humans
[*] Turians 
[*] Asari 
[*] Drell
[*] Krogan
[*] Vorcha
[*] Batarian 
[*] Quarian
[*] Salarians
[/list]
[b]Races that you'd have to ask me about first[/b]
[list]
[*] Hanar
[*] Elcor
[*] Geth
[*] Volus
[*] Robots or AI
[/list]
[b] Races that are banned forever [/b]
[list]
[*] Leviathans 
[*] And even though I don't think I need to say this no you can't be a Reaper that would be silly.
[/list]

That being said I'd like a variety within the squad so keep that in mind!