Is homosexuality a sin?

I have strongly decided to make good preparation for the coming term-end exams. Started my day with one of my paper 'Adolescents and family education'. There is a topic "some concerns of adolescents" - Homosexuality. I wonder every time when I hear the word homosexuality, I dare not to ask any one regarding it, living in a country like India we hardly find people who discuss it openly. But I always want to know exactly what it is. If my students ask me, I should not be paused and say its a bad word without full knowledge.

Luckily we have that topic in our syllabus, I started google the topic; Well, actual meaning of homosexuality is sexual attraction between same sex. Homosexuality begins at the behavior or fantasy level. In homosexuals men are called gay and woman are called lesbian. It's not a genetic disorder. Homosexuals are intellectually, mentally strong they can challenge any one. There is no precise explanation about why people turn homosexual. However, many religions condemn this act; they think homosexuality as a sin. For example, Ramdev Baba said "homosexuality is a disease". But many scientist and researchers say that homosexuality is not a disease.

'Homosexuality is a major concern of physical development of adolescents these days as it is increasing day to day. During this period, passionate friendship develops between the members of same sex. This kind of abnormal and unnatural sexual behavior may lead adolescents to sex related diseases and HIV/AIDS transmission. It will be better that the teachers and parents should give instructions about sex carefully and frankly.' This is the passage given in our book. Is it correct to give such a blind precautions without proper explanation of what it is!!