A joint Canadian/ US study found that male homosexuality has a link to a protein antibody. The release of the study was quite recent in October, 2017.
Researchers have known for some time that a “fraternal birth order” exists that makes it more likely for a younger brother to develop homosexual tendencies. This study sheds light on a reason why homosexuality seems to be more common in the youngest of several brothers.
Mothers of several brothers had higher antibody titers against a specific male protein with every subsequent pregnancy. Consequently, this male protein has an association with the maturation of the brain of the male fetus. In addition, a group of mothers was identified with higher antibody titers against the male protein. This was the group with the highest number of homosexual males. As a result they concluded that the antibodies against the male protein were interfering with the normal brain development process. Because this antibody is specific for the male protein, the antibody does not affect the female fetus with regard to brain development.
Male homosexuality has a link to a protein antibody: discussion by authors
Maternal antibodies against the male protein can cross the membrane between the blood of the fetus and his brain. This is called the blood/brain barrier. Once inside the brain the antibodies can modulate brain development in the male fetus. Therefore the authors believe that these maternal antibodies can inhibit sexual maturation and cause homosexuality.
Antibody titers in mothers who had homosexual sons showed the following distribution. The highest antibody titers are obvious in group 4; group number 1 was lowest.
- women with no sons
- mothers of heterosexual sons
- women who were mothers of gay sons with no older brothers
- mothers of gay sons with older brothers
In conclusion, maternal antibodies block the part of the brain responsible for sexual orientation. Women get sensitized against a specific male protein with repeat pregnancies carrying a male fetus triggering higher antibody titers. Finally the antibodies interfere with male brain maturation.
A Canadian/US team has studied why younger brothers in a family are more prone to become homosexual. They were able to pinpoint this to an antibody against a specific male maturation protein. Women can develop a sensitivity against this protein when it circulates in the mother’s blood. This triggers antibody formation. Antibodies can cross the blood/brain barrier of the fetus.
When antibodies bind to the male protein in the brain of the fetus, it inhibits the normal brain maturation process. The more this happens, the more likely that the offspring will turn homosexual.
At this point we do not know all the answers: other factors may play a role as well in the development of these antibodies. Research will find it of interest to study the possibility of developing a vaccine to prevent the formation of antibodies against the male protein. This is only a beginning, and a lot more research is necessary.