The main aim of the book is to challenge the claim "I am born this way and cannot change". Hence, the book looks at both the extent of genetic influence on homosexuality and if sexual re-orientation can work.
This book is targeted at the man in the street and is divided into 8 sections: a review of important published papers; an evaluation of said papers (published over the last two decades); to give readers a brief understanding, an introduction to research methodology; followed by an introduction to human genetics. After this, he assesses the relative contribution of genes and environment, then does a study of each and finally, discusses the issue of sexual re-orientation.
In a nutshell, the book shows that the claim that "I am born this way and cannot be changed" is not true. For gays, the heritability of homosexuality is only 26% and 43% for lesbians, implying that environmental factors are much more important. Not only does the book show that people are not born this way, it also makes a convincing case for sexual re-orientation, which has a significant success rate for those who want to be changed. All this is helpful for those of us with homosexual friends who are struggling, as we can show them that they are not trapped in what they perceive to be something they cannot change.
Although the book sounds complicated, it's actually very logically arranged. After reading this book, I can now counter those who want to claim that people cannot help being homosexual. I think that in the face of the overwhelming pro-homosexual literature in the public arena, this book is invaluable in helping us to show that the Word of God and science are not incompatible.