Shadow of the Giant
Cincinnatus was the third embryo conceived by Bean and Petra. However, he was stolen by Achilles de Flandres and implanted into a surrogate mother. Cincinnatus was later recovered by his true parents and they discovered that he too carried the genetic manipulation of Anton's Key.
He was taken into space aboard the Herodotus along with his father Bean, and his siblings Carlotta and Ender. The four-person family traveled at relativistic speeds to forestall death, waiting for scientists on Earth to develop a cure for Anton's Key.