This book lists homosexuality as a sexual deviation and then claims that in a 'healthy' society people with sexual deviations are classified as phychologically sick. You point out that the book is written for Christians, so I will phrase my criticism within those confines. The New Testament does not detail homosexuality as a sin and Jesus himself said that the New Testament "overrides" the old testament. This is why Christians are allowed to eat pork and go uncircumsized.
(review of free book)