Claiming that genetic changes which happen after birth can determine whether a man is straight or gay, scientists have recently found out that homosexuality may be triggered by environmental factors during childhood.

Researchers revealed that the finding of the study is highly controversial because it suggests that some men are not born gay, but are turned homosexual by their surroundings and it also raises privacy concerns that medical records could reveal sexuality, reports the Telegraph.

Dr. Tuck Ngun said that he hopes this research helps them to understand themselves better and why they are the way they are.

During the research, the scientists found out that it was possible to tell whether a man was gay or straight by monitoring tiny changes in how his DNA functions after birth, a field known as epigenetics.

Epigenetic changes are known to be triggered by environmental factors such as chemical exposure, childhood abuse, diet, exercise and stress.

Talking about their research done on identical twins, researcher Tim Spector said that it has always been a mystery why identical twins who share all their genes can vary in homosexuality.

He added epigenetic differences are one obvious reason and this study provides evidence for this.