Kays pregnancy is a key plot point in Alien: Romulus, and although she never actually names the father of the baby on-screen, his identity has been confirmed off-screen. Every character in Alien: Romulus goes through hell in the movie no one comes out of it unscathed but Kay, played by Isabela Merced, arguably goes through more hell than any of her friends. At the beginning of Alien: Romulus, Kay confides in Rain that shes pregnant. But when Rain asks who the father is, Kay simply says its some a**hole and refuses to name him.