With Richard's help, Kahlan disguises herself as a Mord'Sith to rescue her pregnant sister Dennee – who is also a Confessor – from a D'Haran prison. When Dennee gives birth to a son, Richard is horrified to learn that it's mandated that male offspring of Confessors be put to death and resolves to save the child, putting him at odds with Kahlan.

Source: Legendoftheseeker.com