DS9 Season 5 Episode 12 The Begotten

Plot

Deep Space Nine's bartender Quark has come into possession of an infant Changeling and sells it to Odo. Odo begins trying to teach his "child" to shapeshift; he is displeased when Dr. Mora, the Bajoran scientist who "raised" Odo, arrives to help.
Dr. Mora and Odo immediately clash over how to best raise the Changeling. Odo, still angry at the invasive methods Dr. Mora employed with him, hopes to reach the infant through encouragement. Mora insists on probing and measuring the creature, to Odo's disgust. Unfortunately, Odo makes little progress using his own methods. Under pressure from Starfleet, Odo has no choice but to resort to Mora's methods.
Using Dr. Mora's equipment, Odo employs electric shocks to prod the changeling into holding several basic forms. Both are amazed when the creature imitates the shape of Odo's face. The moment brings Odo and Mora together—especially when Mora admits to Odo that his caring seems to have helped him form a connection with the baby. Mora's support helps Odo to finally forgive Mora for treating him more as a specimen than as a person. He invites Dr. Mora to celebrate their success with a glass of champagne. But the happy mood is shattered when Odo receives word that the little creature is dying.
Dr. Bashir is unable to save the "child". Odo holds the dying creature in his hands, and, as it dies, the infant Changeling merges into Odo and restores his shapeshifting abilities.
Meanwhile, Major Kira goes into labor, and gives birth as a surrogate mother to Keiko and Miles O'Brien's baby. At the end of the episode, Kira tells Odo about her feelings of loss, after turning over the baby to his parents. Odo tells her he knows how she feels, and the two go for a walk together.