Studies show that the appearance of the person with nonconventional orientation is possible as the effect of hereditary traits or conditions of fetal development in the womb, and the education of the person in society. That is, there is definitely only just acquired congenital or inheritance of sexual orientation.
It is known that in nature homosexuality is manifest among many species of animals. Therefore, it can hardly be considered a mistake of nature or a failure. In human society the chances of having a child with gay is 4-5%. That is true of homosexuals who were born with this quality on the planet more than red people. A sign is rather rare, and he appears not all people openly. After all, upbringing, family traditions are important as well. If a child born with gay, a very strict family and traditional environment, it is likely he will not even know what is gay, and certainly will not openly show their feelings.
Only about 10% of babies in the womb have a so-called "homosexual" gene. But at birth, he appears in about half of infants. Therefore, the issues of heredity in homosexuality is not as critical. Parents with a traditional orientation may have a son is gay, and Vice versa, homosexual father's high percentage of birth of the child is quite traditional. This same law applies even in a pair of identical twins that if one was born gay, doesn't mean the second will be the same.
But it is not only in the genes. If the embryo is a boy in the womb receives a higher proportion of female hormones, they can affect the orientation in the future. Often this effect occurs due to stress or hormonal treatment of the mother. Then at birth the child receives the body of a man, but the thinking and behavior of the boy may be female. Most likely such a child, as an adult, aware of my feminine side and become a homosexual. The same thing happens with the female foetus. If a girl gets too many male hormones during pregnancy, they may manifest in her further behavior.
However, all these changes - a genetic or hormonal manifested only a small fraction of the world population. Every human body contains both male and female hormones, but that does not mean that any person can switch from one orientation to another. Similarly, the features of male thinking is typical 10-15% of women, and female - 15-20% of men. But that doesn't make them gay or lesbian.
However, popular culture can greatly affect a person. Today, information spreads so quickly that many phenomena become widespread. If young men and women see every day that homosexuality is perceived as something normal, interesting and attractive, promote it in the anime, movies, TV shows, young people have a natural curiosity. Why not try if it is fashionable? A ban on this topic in a traditional society is perceived by young people as a kind of rebellion against the older generation, the desire to annoy his parents. Therefore, in today's society many see themselves as gays, in fact, are not being.