Intellectual disability (ID) is a term used to describe a wide range of cognitive impairments that affect an individual's ability to learn and function in daily life. Causes of intellectual disability can be divided into three main categories: genetic factors, prenatal factors, and postnatal factors.

Genetic factors are the most common cause of intellectual disability, accounting for about 50-60% of cases. These factors include chromosomal abnormalities, such as Down syndrome and Fragile X syndrome, as well as inherited genetic conditions, such as Rett syndrome and phenylketonuria (PKU).

Prenatal factors are conditions or events that occur during pregnancy that can lead to intellectual disability. These can include exposure to infections, such as rubella or cytomegalovirus, as well as drug and alcohol use by the mother during pregnancy.

Postnatal factors are conditions or events that occur after birth that can lead to intellectual disability. These can include severe head injury, infection, malnutrition, or a lack of stimulation in the early years of life.

It's important to note that not all individuals with intellectual disability will have a known cause. In these cases, the cause of the condition may be unknown or may be a combination of genetic and environmental factors.

It's also worth mentioning that intellectual disability is not a reflection of an individual's inherent worth or value as a person. Individuals with intellectual disability have the same rights and dignity as anyone else, and can lead fulfilling and meaningful lives with the right support and accommodations.