Psychology

The effects of heredity and environment on human development have been an issue of major concern in the determination of who we are and what we become. Controversies arise regarding the role of heredity and environment in determining the character traits of a person (Powell, 2009).

Genetics issues
    According to Powell, (2007) genes play a very key role in determining the characteristics of a person such as the hair color, eye color, and height. The sum total of a persons character traits are a result of genes interaction. On the other hand one gene may be responsible for a wide range of characters, meaning that, as long as a person has the gene then heshe expresses the trait. Everybody has two genes for one trait. One of the genes is obtained from the father while the other one is obtained from the mother. Some of the genes may be dominant while others are recessive. Incase a person do not have the dominant gene then the recessive gene is expressed. The genetic information of a person is encoded in the DNA.

Environmental issues
    Psychology researchers however, are more interested in factors that are moderately less determined by heredity. These are factors which are subject to environmental influence, like the way a person thinks, feels, and behaves. Given the fact that the determination of a persons character from heredity point of view varies from one dimension to another, it becomes very difficult to understand the intricate relationship between them and also to determine the relative influence of genetics and nature for the development of various human character traits.

Heredity contributes to the development of various personal traits (Kinder, 2009).
    Theorists state that if identical twins are placed under similar environmental condition they will tend to acquire similar character trait, but their theory is disapproved by psychology researchers. Psychology researchers believe that one of the twins may react positively while the other reacts negatively or may fail to react at all. Individuals can react similarly or differently to similar condition depending on their genetic composition. Environmental factors cannot be manipulated to create similar character traits on all individuals (Fedder, 2007).
Correlation between genetics and environment

    A childs character is subject to the balance of their experiences and their parents genetic make up. The environment in which a person is raised, the company heshe keeps, and the parental guidance heshe gets have a very big impact on what a person turns out to be. A child who was born in an abusive society tends to be very abusive also. If such a child is adopted by a family where she is taught good morals the childs lifestyle is most likely to change for better (Powell, 2007).

    Some traits expressions on an individual are influenced by the environment while others like polydactyl, eye color, hair color, free or attached earlobes, and the ability to fold the tongue are not influenced by the environment. A very good example which indicates how the environment may affect the expression of a certain trait is shown by the Siamese Cats. If ice parks are placed on a shaved belly of a Siamese cat, the replacement hair tends to be dark. When the tail of a Siamese cat is shaved and subjected to higher temperature, the replacement fur changes coloration from dark to light. Siamese cats are known to have dark marking on their extremities due to lower temperatures than the normal body temperature (Welch, 1973). The rubella virus is an environmental factor that directly affects an unborn child. This virus crosses the placental blood barrier and if this happens during the early stages of development, it may result to hearing defects, and other adverse damages to the child. Anoxia is another environmental factor that may lead to development of adverse defects to the baby later in life. This is a condition where the body organs of a baby are in severe oxygen deprivation in cases where the baby is entangled with the umbilical cord or is too big that it cannot fit the birth canal properly. (Kinder, 2009)

    Genetics and environments have been shown to play a role in influencing the traits of a person.  Genetics have an impact on a persons physical make up and skills while relationships determine the impact of a persons character and his behavior. People do not become who they are just because they were born, but the environment in which they are raised also plays a very major part.