Most common cause for bilateral conductive deafness in a child is:

AM of the above conditions cause conductive deafness. Otosclerosis usually starts between 20 and 30 years. It is rare before 10 years. Acute otitis media is usually unilateral and presents with severe pain in the ear. Congenital cholesteatoma is rare condition and extremely rare to be bilateral. OME is the most common cause affecting children.