From Shadow Puppets:
"Yes, yes," said Anton, "so I gleaned from Sister Carlotta, God rest her soul. But why did you, and you alone, sneak out of your bed and go into the bathroom and hide in such a dangerous and difficult place? Scarcely a year old, too. So precocious. So desperate to survive. Yet genetically identical to all your brothers, da?"
"Cloned," said Bean, "so ... yes.
However, Bean was only genetically identical to five of his brothers (including Nikolai). The other six were from a separate clone. So how could Bean not know that? He lived with his parents for a year at that point already.