Please note that this is the Narutopedia's article on the episode. If you are looking for the article on the acutal puppets then you should head to Father and Mother. For other uses, see Sasori's parents.
Father and Mother (『父』と『母』, "Chichi" to "Haha") is episode 23 of the anime.
Third Kazekage, being a Human Puppet, was built to retain the chakra the body once had when it was alive, allowing the Third to use his special Iron Sand techniques. The Iron Sand clogged the mechanism in the "Mother" and "Father" puppets, as well as Chiyo's puppet's right arm. Chiyo remembered back to when Sasori was a child and created the "Mother" and "Father" puppets to try to get parental love. Chiyo used a willing Sakura as a puppet and had her dodge the Iron Sand techniques to get close to Sasori.