| A | B |
|---|
| prenatal development | The development of a zygote, embryo, and fetus before birth |
| hereditary | All traits passed down from one generation to the next |
| chromosomes | A threadlike structure that carries genes in living cells |
| genes | The basic unit of heredity |
| dominant traits | Traits that always show in a person |
| recessive traits | Traits that typically do not show in a person unless both genes for the trait are inherited |
| cystic fibrosis | A hereditary disease that results in thick mucus |
| birth defect | An abnormality, present at birth |
| muscular dystrophy | A progressive weakness and shrinking of the muscles most commonly inherited |
| sickle cell anemia | commonly occurs in African-Americans |
| Tay-Sachs disease | accumulation of certain fats in the brain and nerves |
| Down syndrome | caused by the presence of an extra chromosome 21 |
| hyperovulation | An inherited trait that may produce fraternal twins |
| fetal alcohol syndrome | A condition that babies may be born with when the mother drinks during pregnancy |
| rubella | A virus that can complicate pregnancy |
| cerebral palsy | Caused by brain damage around the time of birth. Results in lack of muscle control and paralysis |
| cleft lip/cleft palate | An upper lip divided into two parts |
| spina bifida | Part of the spinal cord protrudes through the skin |
| hydrocephalus | An increase of fluid around the brain |
| environmental | Things and people in a person’s surroundings |
