Liam
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Liam was the name of an unborn child conceived by Saul Tigh and Caprica Six. (Sine Qua Non)
Tigh calls his unborn son Liam (short for William) after his best friend William Adama. This was also his choice of name for a son when he and Ellen were still trying to have children. After the Thirteenth Tribe on Earth wiped themselves out, Liam would be the first pure blood Cylon born in over 2,000 years. However, four months into Caprica's pregnancy, the fetus dies due to a miscarriage. (Deadlock)