The study of identical twins, where one is gay and the other isn’t, makes it harder to prove that genetics are to blame. Identical twins have the exact same genes. Meaning, if genetics are the source of homosexuality, twins will either both be gay or both be straight. However, this is not always the case. Since some pairs of twins have one gay twin and one straight twin, scientists have come up with the conclusion that the hormones children are exposed to in the womb lead to homosexuality.
In the case of a gay child being born without a twin, scientists have come up with the “Big Brother Theory.” The big brother theory states that the more male older brothers a boy has, his chance of being gay increases by 1/3 each time a new boy is born. This is because of anti-bodies that are made during a woman’s pregnancy with her first son. Her body is basically carrying a foreign species because her immune system has never seen proteins on the boys Y chromosome. The natural response is to make anti-bodies to fight the “invader.” The anti-bodies she creates during her first pregnancy affect the boys she carries after, increasing the chance that they'll be gay.
The explanation for one twin being gay and the other not being gay is due to testosterone. The testosterone hormone is an anabolic steroid. Anabolic steroids have properties that develop masculine characteristics in the body. Testosterone masculinizes the body and the brain during pregnancy, and makes a boy a boy. While in the womb, testosterone is formed in the 7th week and released in the 8th week. If a male fetus doesn’t create enough testosterone it can affect the way he thinks. If only enough testosterone is created to masculinize the body, but not enough is created to masculinize the brain, a male will want a male partner because his brain was never masculinized making him want women. A study that helps to prove this theory was covered on a segment of 60 minutes. The specific study that has to do with hormones is the study of Rats. The problem to this theory is why one twin absorbs more testosterone than the other. Epigenetics explains this glitch. Epigenetics is the activation and deactivation of certain genes. The activation of certain genes during early development is key in determining sexual preference. A gene in one twin can be exactly the same as a gene in his brother, but the gene is deactivated and not doing anything. Testosterone is a hormone, and hormones send messages from one cell to the other. If there isn’t enough testosterone to send a message to a certain, unidentified gene, telling it to activate then it never will. Genetic activation, and locating the "unidentified gene," might be the answer to why one twin absorbs more testosterone than another.
In conclusion, there is a lot that scientists don’t know about homosexuality. Scientists are coming up with many theories about homosexuality and where it comes from. However, everytime they make a new hypothesis thousands of questions and contradictions arise. At the moment, there are many more questions about homosexuality than there are answers. The study of homosexuality is a confusing, under-funded, and probably an emotionally charged topic. Many gay people most likely do not want their way of life studied and based off of hormones and genes. Being homosexual is a very personal way of life, and one that they don’t want disturbed. However, other homosexuals probably want to know why they are the way they are. I am curious to see how this research, and the response to the research, will play out in the end. As of now, homosexuality is due to both genetics and hormones.
