Adenoids are small lumps of lymphoid tissue located posterior to the nasal cavity, in the roof of the nasopharynx, where the nose blends into the throat. They play a major role in younger children helping them fight ear, nose and throat infections. After 3 years of age they are no longer needed. Adenoids generally reach their maximum size when your child is between three to five years of age and then begin to shrink by age seven and can hardly be seen in the late teens. Due to infections, adenoids swell up and block the nose which can sometimes lead to breathing problems during sleep. It can also be a major cause of snoring.