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Sexual Orientation Biologically Based

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Is Sexual Orientation Biologically Based or Choice?

Over the years there has been many debates and experiments to try to come to the conclusion of whether sexual orientaion is biologically based or choice. Sexual orientation is a pattern of emotional, romantic, or sexual attractions to men, women or both sexes. Sexual orientation is defined in terms of relationships with others since their identity is based off of their attractions. Sexual orientation can be noted through behaviors such as holding hands or kissing, sharing goals and values, mutual support, and ongoing commitments. Sexual orientation can be broken down into three categories heterosexual, homosexual, and bisexual. While this break down may seem very black and white, there are …show more content…

A few studies have shown that homosexuality tends to run in families. Many believe nature and nurture play complex roles since most people experience little to no sense of choice about their sexual orientation. The likelyhood that the brother of a gay man also being gay is about four times higher than normal. Three research methods have been used to explore the existence of genetic influences on sexual orientation: family studies, twin studies, and molecular genetic studies. Each method provides useful information. Family studies can answer questions such as, Does the trait of interest run in families? Family studies can also be used to help decide if the same genes are important in both sexes. They also look for patterns in how a trait is passed down through generations making it possible to get an idea about where predisposing genes could be located. Studies have shown the average rate of homosexuality in men with gay brothers is approximately nine percent and for females six to twenty-five …show more content…

Researchers have narrowed the region where this gene resides to the X chromosome, Since sons get this chromosome from their mother. Studies of DNA markers on the X chromosomes of siblings has narrowed the search to an area called XQ28. It is made up of hundreds of genes and can be found on the tip of an X chromosome. There has also been some clues that genes are located elsewhere and could possibly have an identical effect on sexual orientation. A team from North Shore University, Illinois, further researched these genes by comparing DNA from 1077 gay and 1231 straight men. They scanned the men’s genomes, looking for a single letter difference in their DNA sequences. From this they were able to focus on two genes whose variants seem to be linked to sexual orientation. One of the genes is located on chromosome 13, which is active in a part of the brain called the diencephalon which contains the hypothalamus. Another gene was discovered on chromosome 14 and is mainly active in the thyroid, but also the brain. This gene is called TSHR, it makes a type of protein that clings on to a hormone that stimulates the thyroid. The gene plays an important role in controlling thyroid function. There is some evidence that the brains of homosexuals may be different from those of heterosexual men and women. The differences have been found in the hypothalamus. Studies done in the Netherlands and in Southern

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