This option is only suitable for unilateral atresia where normal hearing is present in the other ear.
Many unilateral children do ok without aiding. The main difficulty these children will have is locating the direction a sound comes from and also hearing in noisy backgrounds (e.g. restaurants, noisy classrooms etc).
Traditionally, children with a unilateral hearing loss were not aided as they tend to hear well in quiet listening environments (e.g. home). Unfortunately many environments, particularly school classrooms, are not quiet listening environments. Current research now supports the case for aiding children with a unilateral hearing loss. Aiding these children gives them the best access possible to sound in all environments and stimulates the auditory nerve and pathways, which is particularly important during those formative early childhood years.
If you choose not to aid your child, it is vital that you regularly have hearing assessments and monitor their speech and language development.