Research shows that environmental factors and experiences can alter the genetic make-up of a developing child.[13] Exposure to prolonged stress, environmental toxins or nutritional deficits chemically alter genes in the foetus or young child and may shape the individual's development temporarily or permanently. Violence and maternal depression may also impair child development and mental health.[14] When trauma occurs at critical times of development for the foetus or young child, the impact on specialized cells for organs such as the brain, heart, or kidney can result in underdevelopment with lifetime implications for physical and mental health.[13] For instance, a study on Iraq showed the rate of heart defects at birth in Fallujah to be 13 times the rate found in Europe.