Illustration/Devdutt Pattanaik

In the beginning, people said homosexuality is unnatural. Then scientists showed them that hundreds of species of animals do indulge in homosexuality. So people started saying homosexuality may be natural, but it is best restricted to animals. Amongst humans, it is a social disease. This unscientific understanding is popularised by many religious leaders, who are clueless about science, though they insist that the Vedas/Quran/Agama/Tripitaka/Talmud are essentially scientific.