Nature vs. nurture is an age-old debate: do environmental or hereditary factors have a greater effect on physical development? Most scientists think it is a combination of both, although there have been numerous studies performed on both sides of the debate that attempt to prove their specific point. Heredity is responsible for some physical characteristics and growth aspects in both fetal and childhood development. However, both environment and genetics seem to play a role in overall physical development.
Genes are the determinants of heredity, and each individual carries genes from the mother and the father. Characteristics such as height, weight, skin colour, eye colour and hair colour are all determined through the balance of genes in the body. Genes are responsible for cognitive and mental processes as well as physical features, and they are passed down through generations.
Dominant and Recessive
According to ThinkQuest.org, there is both a recessive gene and a dominant gene for every individual personal characteristic. For instance, if one parent has dark hair and the other has light, the dominant gene will determine the colour of the resulting child's hair. Genes are responsible for factors that determine a wide variety of hereditary physical characteristics.
Physical development in children is often measured in milestones. Children are expected to reach certain measurable developmental milestones at specific ages. For instance, by the age of 3 months a child should be able to roll over. At 6 months they should be able to sit up without assistance, and at 12 months most will have at least attempted to stand up or walk. These developmental milestones are used by physicians to determine if a child is making adequate physical progression throughout their growing years.
Although genes do play a large part in the developmental process, the environment also has a role in determining physical characteristics and development. If a foetus is exposed to pollutants or chemicals in the womb at specific stages in the developmental process, it can alter their deoxyribonucleic acid, or DNA, and cause mutations that may not otherwise have occurred.
Fetal alcohol syndrome is caused by the foetus having been exposed to alcohol in the womb. This can result in physical and cognitive malfunctions that are not connected to hereditary influences. In addition, nutrition plays a large role in the development of certain characteristics, or the lack thereof. Even stress can alter DNA and cause developmental delays. In addition, stress, pollutants such as cigarette smoke, and malnutrition can slow the physical and cognitive development of children as well.
Physical development has to do with more than just surface characteristics, but also brain growth and health of the internal organs. Many times, parents inadvertently pass genes on to their children through their DNA that may contribute to physical developmental disorders. Genetic disorders are responsible for cerebral palsy, spina bifida, and cystic fibrosis, as well as a wide variety of physical disabilities. In cases of birth or hereditary disorders, the gene may be attributed to one or both parents. Some disorders require that both parents carry the gene.
Studies have shown a hereditary link between sports performance, musical ability and cognitive ability as well. There is a DNA component that determines an individual's capacity to perform in a given area. Although these characteristics are determined to some degree by genes, environment is also a determinant in the process of physical growth. In addition, motivation, determination, nutrition and training all play a role in achievement in a given area.