Corey was thinking that if her son was willing to be Sonny’s stepfather, at least Duncan’s small family would have a child. Maybe because of Sonny, Liberty might even have another one in the future.

Sonny always wanted a little sister.

Everyone assumed that the baby in Serenity’s belly was a boy.

Sonny, wanting a little sister, would pester his mother to give birth to one. This way, Duncan could have his biological child, even if it was a girl. Corey would be pleased as long as it was Duncan’