Ender has come home with his monitor removed. Ender's father is upset because at this time he is under the impression that the IF doesn't want to use any of his children. Ender is a "third." That was not a thing to be proud of during that era. Ender's father is upset because he will have to be viewed as someone who irresponsibly had three children and that will embarrass him. On this same train of thought,
"He is later than most in having the device removed—six years old—thus separating him from his peers. He is also the third child of his family, in a futuristic society that seldom allows more than two children. Although Ender is a legal "Third," he is still an object of scorn and derision.