Turned out to be a gay is not only determined by social factors, but also a biological factor. More startling statements from scientists who said the brothers more siblings you have, the possibility of becoming a bigger gay.

Actually when the man's sexual orientation determined? A study conducted in Canada recently mentioned deviant sexual behavior of a man determined since they were in the womb.

Professor Anthony Bogaert of Brock University, Ontario, Canada, studied 944 heterosexual and homosexual men of their male siblings from the same mother, and brothers both non-adoption or biological half-brother.

Bogaert found homosexuality more experienced men who have male relatives from the same mother. The more brother of the man they have, the possibility of being gay or in the greater psychological terms is called fraternal birth order effect. However, these phenomena are not found in men who have half-brother or foster-brother.

"Even though a person has male siblings, and had never spent time together growing up, the possibility of being a gay stay there. And it refers to the possibility that some non-learning factors or non-environmental that affect sexual orientation," explained Bogaert.

But no means has many brothers and sisters so he automatically becomes a homosexual person. This study found an increase of sexual orientation to be gay to three percent in each of boys born to mothers who previously had had some boys. But it is not found in boys who have female siblings.

While other studies conducted to determine how pregnant women can react to the possibility that sexual orientation influences the development of the boy's life in the future.

"These results support the claim that the content affects the development of sexual orientation and fraternal birth order effect is obtained from the feminine maternal instincts when baby boy was conceived and development," as in Bogaert reports in Proceedings of the National Academy of Sciences (PNAS) edition first.

From there emerged the theory if the expectant mother's body considers male fetus is a foreign object, then the antibodies formed that will be strong along with the development of the fetus.

"If this theory is correct, then the relationship between the antibody genes from the male and the mother's sexual orientation a baby boy she is carrying will affect sexual differentiation in the child's brain and it affects the child's sexual orientation to the future," said Bogaert, who is planning to do research supporting sexual orientation relationship with the antibody genes from the male pregnant women.

These findings welcomed gays, such as comments Andy Forrest, a spokesman from Stonewall gays who claim this discovery proves being gay is not a lifestyle choice, but it was a choice that is determined since the person is still a fetus. Forrest expects this discovery could open the eyes of the public, that gays and lesbians deserve equal treatment in society.