Child abuse in all its ugly manifestations is clearly detrimental. Physical and sexual abuse can result in lasting emotional handicaps and can prevent victims from having normal lives. The effects of child abuse can show up later in work habits, personal relationships and in parenting. Family breakdown is usually bad for kids, especially if their parents are at war. All of these things have the effect of holding them back permanently from what they might have achieved.
Real poverty is bad for kids.
Persistent hunger, inadequate and unhealthy housing, and the absence of other basic needs can do real damage to children and prevent them from developing their potential. However, an important distinction needs to be made here. Merely having less than many others or than the average in the community does not impinge on children s development or interfere with their ability to do well in school. What harms them is real deprivation. The absence of those very things they need to develop and grow and remain alert and healthy is what does injury.