Gay couples wait in lineto apply for a marriage license in Salt Lake City
Tarah Camarillo (L-R), her partner Nicole Barnes, Leighton Hilburn and his partner Preston Perry wait in line with hundreds of other people to apply for a marriage license at the Salt Lake County Clerks office in Salt Lake City, Utah, December 23, 2013. Reuters/Jim Urquhart

Scientists have discovered two DNA stretches linked to homosexuality in men. The confirmation of a "gay gene" is expected to support the argument that homosexuality is biological and not by environmental influences.

The results of the controversial study by researchers from the Chicago University could also pave the way for discrimination against homosexuals. Insurance companies could require genetic tests to determine if their clients are gay. Genetic tests could also be used by pregnant women for selective abortion if they don't want to have "gay babies."

The Chicago University researchers analysed the DNA of more over 400 pairs of homosexual brothers who were asked to participate for research purposes at Gay Pride festivals over the years. Researchers came across two stretches of DNA associated with homosexuality.

Reports said it is still a mystery which of the genes contains the specific stretches and how they particularly affect an individual's sexual orientation.

The results of the recent study seem to support a 1993 study revealed in an annual conference by the American Association for the Advancement of Science. It was the first study to reveal evidence of the "gay gene" which created a controversial debate and inspired other scientists to find the genetic link.

Northwestern University's Dr Michael Bailey who contributed to the research in the recent study said it was "the biggest of its kind." He remarked that a person's sexual orientation is not a matter of choice since their findings suggested a genetic link. He said they have proof of what determines a man's sexual orientation.

When asked about the subject of prenatal testing in the future, Mr Bailey said he does not object to the test, but parents should not be allowed to kill their unborn child just because he or she has the genetic link to homosexuality. But he believes they should be allowed to have access to that kind of information.