Early on in the play, we learn that Titania has been taking care of a "lovely" Indian boy and spends all her time lavishing him with love and affection (2.1). This has caused a huge rift between Titania and her husband Oberon, who wants the boy to be his personal "henchman" (errand boy/attendant). Oberon is also bitter about the fact that Titania keeps the kid to herself while ignoring Oberon. According to Puck, Titania "perforce withholds the loved boy, / Crown him with flowers, and makes him all her joy" (2.1.26-28). Although the boy doesn't have a speaking role in the play (and doesn't even appear on stage in some productions), he's a pretty important figure in A Midsummer Night's Dream.
First things first: Who exactly is this little boy and where are his real parents? According to team Oberon, the little boy is a "changeling" Titania stole from "an Indian king" (2.1.23; 22).
Side note: If you were thinking Shakespeare was referring to the Angelina Jolie movie—we're sorry to disappoint. Stephen Greenblatt tells us that a "changeling" typically refers to "a child left by fairies in exchange for one stolen, but here [the term refers] to the stolen child." "Changelings" are an important part of English fairy lore and Shakespeare often makes references to them in his plays, like The Winter's Tale (3.3) and Henry IV Part 1, where King Henry says he wishes some fairies had switched his rotten kid for a better son at birth (1.1).
Titania doesn't deny that she's got the kid with her, but she tells a different story about how she came to care for him. According to Titania, she used to be friends with the kid's human mother back in India but "she, being mortal, of that boy did die" (2.1.140). Translation: The woman died in childbirth, so Titania is fiercely committed to raising the boy for her friend.
We also want to point out that Shakespeare makes a very big deal out of the fact that the boy is from "the farthest step of India," which is also the place from which Oberon has travelled to attend the wedding of Theseus and Hippolyta (2.1). In the play, India is imagined as an exotic, far-off place, where the evening air is "spiced" and where the sails of merchant ships "grow big-bellied with the wanton wind" (2.1.133). Shakespeare wrote this play in the late 16th century, when England had already been trading with India for a few hundred years, so we're not surprised at Shakespeare's geographical shout-out.
Like we said, the little boy is the object over which the Fairy Queen and King fight, so, in many ways, he's emblematic of the couple's domestic power struggle. When Oberon succeeds in taking the boy from Titania (by dosing her with magic love juice and forcing her to fall deliriously in love with Bottom), Oberon basically strips Titania of a mother-child type relationship that is obviously important to her.
Some critics see Oberon and Titania's fight as a dramatization of what often happened in upper-class houses in Shakespeare's England, where boys of a certain age were taken out of their mom's care and sent off to school (with other boys and male teachers). Scholars Gail Kern Paster and Skiles Howard argue that "The play identifies the emotional violence of this radical separation of mother and son with Titania and her ferocious refusal to let her godson go. Oberon parodies and ridicules her maternal attachment and care by putting the monstrous Bottom in the boy's place."
Brain Snack: In 1862, a British magazine called Punch published a Midsummer Night's Dream-inspired political cartoon commenting on the US Civil War. The provocative cartoon depicts Oberon as President Lincoln and Titania as the State of Virginia. The Changeling is depicted as a young slave boy, over whom Lincoln and Virginia are fighting.