Sylvie Clark was a Vault 22 dweller in 2097. Unlike the rest, she wasn't crazy and thought the other Vault 22 citizens were evil.
In 2096, Sylvie was trapped in a bear trap, and was found by Randall Clark. Randall hesitantly freed her. Finding out her story was just like his, they began a relationship. Before long, she became pregnant with a son, Michael Clark.
According to Randall Clark's computer entry on 9th September 2100, he states how the situation scares him, indicating that Sylvie probably only told him recently about being pregnant.
Unfortunately, on the March 5th, 2101, the baby was born breech. Randall had to do a C-Section, which he thought was too late. Sylvie did not wake up from the anesthetic, and Michael died.