This book examines the frequent statement made by homosexuals and their supporters; “I am born gay and so I cannot change.” The author, a trained clinical geneticist whose two doctorates are in the field of genetics, approaches this issue objectively by reviewing 20 years of high-quality research papers published in reputable international journals. This is done in order to examine the growing public and political acceptance of the view that homosexuality is entirely biological and thus immutable. Written for the general public, this book is devoid of technical terms as far as possible and avoids complex mathematics and statistics.