Dna Of 40 Pairs Of Gay Brothers example essay topic

This article attempts to identify the biological causes of homosexuality. The article introduces the different ideas that many different scientists and psychologists have about the causes of homosexuality. One idea focuses on one of the most obscure features that distinguish the two sexes- how our inner ears respond to clicking sounds. The theory behind this idea was that hormone levels in the womb, rather than genetic or social factors, determine whether some people become gay or lesbian. To prove this relationship tests were conducted on girls who shared their mother's womb with their twin brother to find if there were higher levels of male hormones. It was concluded that higher-than-average levels of hormones before birth and a part of the brain had influenced their sexual preferences.

It was the first serious claim by scientists to have discovered a physiological characteristic that could distinguish lesbians from straight women. Other researchers claim that lesbian woman have masculinised hands, with ring fingers that are longer than their pointer fingers, and gay men having feminine hands. The possibility that a person's sexuality can be determined by simply looking at their hands demonstrates why the scientific study of gayness inspires both fury and fascination. Researchers have broadened their search for clues to explain homosexuality, investigating factors such as the birth order of gay people, their number of siblings, parental age, finger prints penis size, age at puberty, left- or right- handedness, and mothers stress levels during pregnancy. An epidemiologist conducted a study, which found that the genetic influences on homosexuality are weak.

More importantly he believes that homosexuality is an essential part of human sexuality. Many gay people consider all this research to be a waste of money, as it is an unwanted distraction from the real issues of concern, such as violence and discrimination. A more famous discovery was the isolation of a gay gene. The DNA of 40 pairs of gay brothers and it was found that most of them shared a similar region of DNA near the tip of their X chromosome. The discovery sparked an ethical debate about whether this could lead to the abortion of gay fetuses in future. Several years later a similar study was conducted on 52 pairs of gay brothers, and they had found no evidence for this gene.

Scientists who study evolution do not believe in the genetic basis for homosexuality. They argue that any gene that is responsible for making people gay or lesbian should have disappeared long ago because homosexual people have fewer children. One well-accepted, but not generally known, factor influencing gayness in men is the number of elder brothers. Population studies carried out over the past years shows the chances of being gay increases by a third for every elder brother a man has.

The explanation for this is that somehow a mother's body remembers how many sons, she's had. With each subsequent one she alters their fetal development so they are exposed to more male hormones, which increases their chances of being homosexual. STATE THE SCIENTIFIC CONCEPTS THAT ARE INVOLVED IN THE ARTICLE The article discusses: h Hormone levels that determine whether some people are gay or lesbian. h Levels of hormones and testosterone in the first months of life. h The research of several factors to explain homosexuality such as fingerprints, penis size and stress levels during the mothers pregnancy. h Investigating the genetic influences on homosexuality. h The discovery of a possible gay gene in the region of DNA on the X chromosome. h The study of evolution, which contradicts any possibility of any genes that, is responsible for making people gay or lesbian. h The amount of hormones they are exposed to while they are in their mother's womb. h The higher levels of male hormones which affects both reproductive organ size and sexual orientation. STATE WHO THE SCIENITSTS WERE WHO PARTICIPATED h Psychologist, Dennis McFadden h University of California Researchers h Psychologist, Dr Marc Breedlove h Epidemiologist, Dr Michael Dunne h Dr Dean Hamer h Dr Michael Bailey h Professor Nick Martin h Psychiatrist, Dr Ray Blanchard LIST THE SCIENTIFIC ACHIEVEMENTS THAT WERE DETAILED IN THE ARTICLE h The discovery of a physiological characteristic that could distinguish lesbians from straight women. h The discovery of a possible gay gene in the region of DNA on the X chromosome. h The discovery of many influences on sexual orientation. HOW DID THE SCIENTISTS ACHIEVE THEIR OUTCOMES h To prove the relationship that physiological characteristics of people had with their sexual preference, Dr McFadden tested the response to quickly repeated clicking noises that girls who shared their womb with their twin brother had. This explained why most bisexual and lesbian women have masculinised inner ears. h Dr Dean Hamer announced that he was close to isolating a gay gene after studying the DNA of 40 pairs of gay American brothers.

He found that most shared a similar region of DNA near the tip of the X chromosome. h Many scientists have developed theories on the influences on sexual orientation. These theories are developed several ways such as; Dr Ray Blanchard, who carried out population studies to prove that the number of elder brothers they have influences gayness in men..