Intellectual disability is a term used when there are limits to a person’s ability to learn at an expected level and function in daily life. Levels of intellectual disability vary greatly in children. Children with an intellectual disability may have difficulty expressing their wants and needs, and might struggle with functional skills needed to care for themselves. Intellectual disability could cause a child to learn and develop more slowly than other children of the same age. It could take longer for a child with intellectual disability to learn to speak, walk, dress, or eat without help, and they could have trouble learning in school. Intellectual disability can be caused by a problem that starts any time before a child turns 18 years old – even before birth. It can be caused by injury, disease, or a problem in the brain. For many children, the cause of their intellectual disability is not known. Some of the most common known causes of intellectual disability –like Down syndrome, fetal alcohol syndrome, fragile X syndrome, genetic conditions, birth defects, and infections – happen before birth. Others happen while a baby is being born or soon after birth. Still, other causes of intellectual disability do not occur until a child is older; these might include serious head injury, stroke, or certain infections.