To what extent does genetic inheritance influence behavior

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To what extent does genetic inheritance influence behavior?

         For years and years, there has been endless debating on whether human behavior is predetermined by genetic inheritance. The question that behavior was due to the transmission of genetic material from parents to offspring or construction by the surrounding environment had one of humanity’s greatest mysteries (medpdia). However psychologists and scientists have finally concluded that human beings are a product of combination of nature and nurture. No longer does any researcher with any reputation claim one over the other, it has now become a question of how much. Genetics definitely do influence our behavior, but to what extent? Trying to solve this question, psychologists and scientists look towards research on twins for clues. The main feature of these studies is that identical twins share the same genetic inheritance. Therefore, this allows psychologists and scientists to analyze the difference in twins’ behavior and conclude which of two: genetic inheritance or environmental factor, have influenced their behavior the most. Supported by the studies of identical twins’ similar IQ scores and sexual preferences, genetic inheritance influences behavior to large extent.

The study of twins in the psychological world today elucidate the best clues into how genetics influence behavior. Researchers enthusiastically seek out twins that have been separated from birth to study their similarities and differences. Thomas Bouchard from the University of Minnesota has conducted studies on over 8000 pairs of twins some identical and some not. According to Thomas Bouchard’s twin studies, which tested the twins’ Intelligence Quotient (IQ), intelligence is “69-78% heritable”, concluding that since IQ is heritable more than 50%; therefore, genetic inheritance influences human intelligence as well as their behavior to large extent. Intelligence is an integral component of how our brain operates, and the fact that it can be heritable raises serious questions about how we can develop it. Moreover, a case study on the twins Ms. Herbert and Daphne by Bouchard illustrated that although they were separated in early stage of their life, they showed remarkably similar personalities and mannerisms (Bouchard, IQ studies). Even though Ms. Herbert and Daphne were both brought up in different environments under different step-parents, the fact that they possess similar characteristics to each other concludes that genetic inheritance to large extent determines human behavior. Therefore, the twin studies and the case study on Ms. Herbert and Daphne supports the conclusion that although environmental factors do effect human behavior as well, genetic heredity plays a massive role in our development in personality or characteristics.

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Intelligence however, is just the beginning to understanding how truly heritable traits of our minds are.  Studying human sexual orientation is an integral part of our understanding of genetic influence. If we truly are products of our genes or environment, how much of what designates our sexuality in the future? According to the case study on Australian identical twins, homosexuality was 20% heritable in men and 24% in women. Moreover, National Cancer Institute researcher reported that “many homosexual men appear to inherit a gene from their mothers that influences sexual orientation”. Adding to this report, Dean Hamer, the chief ...

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