Humans are born 12 months too early. Gestation should be 21 months. Humans evolved to become the pre-eminent animal in the world, but our big brain, bipedalism, and small female pelvic outlet have caused us to pay the price of being born too soon with all of its disadvantages. Early birth has an impact on diseases and disorders encountered by the otolaryngologist, including otitis media, laryngomalacia, tracheomalacia, congenital vocal cord paralysis, subglottic and tracheal stenosis, gastroesophageal reflux, congenital micrognathia, and congenital nasal alar collapse. Many of these conditions improve or resolve completely in the first year of life as an infant's immune system and anatomy matures. Knowledge of this evolutionary process can help us understand why some infants will grow out of certain diseases and disorders encountered in pediatric otolaryngology, while others will not. (C) 2004 Elsevier Ireland Ltd. All rights reserved.