This "never-before-reported study of why women have sex was conducted online between June 2006 and April 2009.....The survey began by asking the women if they had ever had sex for one of the 237 reasons we identified in our original study." The study involved 1,006 women from a variety of backgrounds. "The basic biochemistry of attraction is the number one reason women give for why they have sex." Women unconsciously utilize two types of evolutionary instincts to seek out and find their mates--they are "Genetic benefits" that "are the high-quality genes that can endow a woman's children with a better ability to survive and reproduce." "'Resource benefits,' are the second type that include food, shelter from the hostile forces of nature, and physical protection from aggressive men, help a woman and her children survive and thrive." This is a fascinating non-fiction book. It's full of information that most readers will never have even imagined. One of the book's first examples of this is "the scent of sexiness." Women's sense of smell enables them to help select their best possible mates by the odor of the males "pheromones." A male's scent enables women to identify good hygiene and clues to the male's immune system and body symmetry and whether mating with them will produce superior offspring. That's only a tiny sample of the fascinating information supplied by this book. What will surprise many readers is many of the secondary 236 reason's women have sex. This book also seems to prove that sex can greatly relieve stress and also cure many of women's headaches. Surprise, surprise-the fact seems exactly opposite of the public's beliefs. Women also have sex to gain or regain self-respect, to gain status, to be popular, to attract a mate and sometimes just because she wants to find out "what all the fuss is about." Loneliness, revenge, charity, to protect their partner from other predatory women, and simple boredom are also important reasons. This book should be required reading for women because of the insights it provides them into human sexuality and motivation, but it's also fascinating information for males. Once a man understands the information in this book he will become a much more successful sexual partner with much happier partner(s). The book includes excellent notes, sources and a good index. Somewhat surprising to this reviewer, the book is definitely a page-turner. It's excellent. This book will also help readers of another recently published book by Eve Kingsley that I can't name unless I don't want this review published. It is listed on the Amazon listing for this book as a possible combination purchase as well as separately. The Kingsley book is also fascinating, but this book helps explains the thought processes behind its subject matter. I'd suggest the reader refer to my review of the Kingsley tome, but Amazon, or it's computer programs(?) doesn't seem to allow any reader reviews of it to be published?