The Sexual Brain [Paperback]

This book summarizes research on sexual behavior and the brain for general readers. Topics covered include: why most organisms use sex for reproduction, pre- and post-natal hormones and sexual development, brain structure, hormones and sexual behavior, instinct and courtship behaviors, hormones and behavior during pregnancy, sexual dimorphism in behavior and brain structures, sexual orientation and genetics, and gender identity and hormones. Research cited in the book involves a variety of organisms, from yeasts to birds, from rats to humans. End material includes sources and suggestions for further reading, a glossary and an index.

LeVay's style is informal to the point of being flippant. For example, in a discussion pointing out the importance of a mothering practice amongst rats for future sexual behavior (licking the anogenital region to promote urination), LeVay launches into a discussion of whether the practice is uncouth, contributing to our feelings of revulsion towards rats. He goes on to point out that even attractive animals can have unattractive behaviors, such as koala mothers who feed their offspring feces. In a book of this nature, considering a normal animal behavior in a subjective light such as this is inappropriate, and emphasizing it by going off the topic to an unrelated behavior in another animal, that isn't even related to the main topic at hand (sexual behaviors) is going way overboard. LeVay may consider such an approach humorous, but it takes away from the credibility of the remaining material.

Rather than present a simple collection of facts about hormones, behaviors, and the brain, there is a central, underlying argument, and each chapter builds toward this argument, that there is a hormonal, if not genetic explanation for homosexual behaviors in humans. The evidence of hormonal effects on animal behavior is very clear, and the examples that LeVay provides are quite interesting. I still come away from the book with the feeling however, that I would have preferred LeVay to present his argument more explicitly from the beginning of the book rather than taking such an implicit (and almost sneaky) approach.

Overall Opinion:
Although Simon LeVay brings up many interesting points in his novel, The Sexual Brain, he fails to delve deeper into these ideas. Therefore, the book is well suited for the general reader with a curiosity into the biological aspects associated with human sexuality, but may be simplistic for those who already have neuroscience knowledge. Although I enjoyed reading the book, I finished most of the chapters wanting more. LeVay brushed over most of his thoughts and ideas and I wished he'd gone more in depth. At some points, the language he wrote in came off as almost childish. All of the experiments he used to support his ideas only had brief summaries instead of a more complex discussion of the results and what they might mean. LeVay does include his sources listed by chapter so the more interested readers can pursue the scientific literature that discusses his ideas and the research in the area. Despite these shortcomings, it was still an interesting book and would certainly be a pleasurable read for the general reader with an interest in human sexuality.

Synopsis and Style:
The Sexual Brain looks at how individuals develop into males and females, both in the womb and during growth and puberty, and the effects of many hormones in this process. It also looks at the differences in male and female brains, especially the hypothalamus, as well as courting and maternal behavior. Lastly, LeVay looks at a few theories behind sexual orientation and gender identity. The book is written for the general reader, one with no background knowledge in biology or neuroscience. All discussion has been brought more into laymen's terms and anything readers need to know to understand it is given to them. Each individual chapter can be read and understood independently from the others and the chapters each have summary paragraphs at the end for those readers who don't wish to read the entire section. There is also a glossary of important terms in the back of the book although these terms are also defined as they appear in the text. LeVay also refers readers back to other chapters if he brings up an idea that he's discussed previously, allowing readers to refresh their memory of what he's discussed before.

Specifics Aspects of Review:
Brain Organization and Background (Ch. 1, 2, 4, and 5)
LeVay begins his book with a few chapters covering the background on how we define sex and sexual behavior, why we're sexual creatures as opposed to asexual, and how the brain is organized and studied. This is one of the strongest aspects of the book as LeVay does a very good job making a lot of complex topics accessible to general readers. The background chapters were easy to understand yet still would allow readers to feel they are getting a good overview of the subjects. The argument for the success of sexual reproduction is really interesting and is something I'd never thought of before in terms of its help in the survival of a species. The background on the brain touches on a few of the major structures but focuses on the hypothalamus, the subject of many of LeVay's discussions in later chapters.

Differences Between Males and Females (Ch. 3, 9, 10, and 11)
LeVay looks at many differences between males and females including fetal development, actions of various hormones, and the sizes of multiple brain regions. He examines how the presence or lack of hormones can alter development and also looks at when these hormones are at their peak levels. He also looks at the sexually dimorphic medial preoptic region. Some of the most interesting studies look at how exposure to various levels of hormones during prenatal life or the mother having a difficult pregnancy can lead to more male or female typical behaviors. He also goes into sex differences beyond sex, such as performance level differences between males and females in certain tests. I would have liked to see more discussion on what structurally or hormonally could be behind these differences.

Human Behavior (Ch. 6, 7, and 8)
LeVay includes chapters in The Sexual Brain on human behavior in sexual intercourse, courtship, and maternal behavior towards offspring. In the chapter on intercourse, LeVay discusses the hormones and neuronal pathways that are in action during sex, leading to erection, ejaculation, and orgasm as well as lordosis in rats. Although interesting, I felt this chapter didn't fit as well with the other chapters of the book as it was less about sexuality and more about the pure act of sex. In the chapter on courtship, LeVay looks only at studies of birds and monkeys and the parts of their courtship such as birdsongs and eye contact. This isn't tied back very well to courtship in humans. The hormonal changes during pregnancy that affect maternal behavior are very interesting and LeVay looks at multiple studies involving hormone injections into non-pregnant rats and the resultant behaviors. He also touches on the evolutionary split of the hormone vasotocin into the two hormones vasopressin and oxytocin since oxytocin plays a role in orgasm, giving birth, and suckling.

Sexual Orientation and Gender Identity (Ch. 12 and 13)
The Sexual Brain concludes with two chapters that address what might be the biological roots behind homosexuality and transsexuality. This was the section of the book where I most wished LeVay had created a more in depth discussion. There is much controversy surrounding these two ideas and what leads to them yet the book just skims the surface behind some potential biological roots. There are some interesting studies involving twins, including some who were separated shortly after birth, but some of these are still inconclusive. He spends a lot of time on studies looking at the regions of the brain that differ in size between men and women and how the brains of homosexuals compare. I wish LeVay had looked more at the observation that lesbians and gay men tend to be less consistently right handed than the general population and what that could mean in regards to developmental differences. Also, LeVay informs readers in his introduction that he himself is a homosexual and it would have been interesting to hear more on his own opinions behind homosexuality. There is currently no strong evidence for a genetic component for transsexuality but LeVay does mention a disorder known as 5-alpha-reductase deficiency in which individuals experience an apparent sex change at puberty, appearing to change from female to male. Only a short discussion is devoted to what the gender identities of these individuals could tell us about the roots of transsexuality.

Recommendation:
As I've said, I did enjoy reading The Sexual Brain despite the fact that I wanted more details and depth because I am not a general reader when it comes to topics of biology and neuroscience. That being said, this would be a really good book for general readers wishing to learn a little more about the roots of sexual behavior and feelings. LeVay is very successful in appealing to the needs of this type of audience and book gives a good first taste of these ideas. More knowledgeable readers can enjoy LeVay's discussion but need to be prepared for the fact that it is much more general than what they may be used to or expecting.

It's a small book composed of only about 120 pages of actual text, which should appeal to those customers who don't like to purchase books with high page numbers, however, that is no indicator to the quality of the text inside. LeVay covers a variety of topics concerning the origins and beliefs into our sexuality and inserts his novel and sometimes unorthodox ideas, which prove to be fairly interesting most of the time.

Synopsis :
LeVay covers every aspect of life and biological aspect that controls our sexuality. It delves into the differences between genders as well as the process of courtship. The book is written with the casual reader in mind. There are no terms that are too big to understand or no concepts too difficult to grasp. Everything is presented in such a way that someone with no knowledge of neuroscience would be able to pick up most, if not all, of the the ideas that LeVay is trying to share with us. The chapters are short, which provide that psychological advantage of completion that was present in the Harry Potter series to me. LeVay also helps us with short term memory problems by referring us back to previous ideas that he's presented previously.

Parts of the Book:
The beginning of the book is devoted to a lot of background on sex and our behaviors regarding sex. It goes into a pretty interesting discussion about why we evolved into sexual creatures as opposed to sexual creatures, which is something I never thought about. He presents the idea that we evolved into sexual creatures to rid our species of harmful mutations, but also presented a world where a mutation allowed someone to reproduce asexually. Additionally, he goes over the hypothalamus, whose purpose in our body is nowhere indicative of the small size it occupies in the brain.

LeVay spends several chapters looking at fetal development and the differences that exist therein. I had always believed that development is determined by the presence of hormones, but LeVay lets us know that in some cases it is the absence of some hormones that can affect development. I liked how he provided details on this aspect that he went over. For example, levels of testosterone from two days prior to birth to six days after can drastically affect the size and number of the sexually dimorphic nucleus, which obviously enough is larger in males than females (due to the testosterone). He examines some studies about how the exposure to hormones or other scenarios can lead to different behaviors.

He also touches base on the actual action of sex and the biological pathways that occur during the different aspects of it including hormones such as vasotocin (which actually is very similar to two very important hormones -- vasopressin and oxytocin). He starts off with courtship and examines cases involving birdsongs in birds or eye contact with monkeys and somewhat sidestepped discussing human courtship. I suppose that's because we experience it in our everyday lives and there's no reason to discuss it in the book. He takes a lot of space to discuss pregnancy and the changes that occur and examines studies where hormones were injected into rats.

The last few chapters discuss some of the more controversial aspects in the world today: homosexuality and transsexuality. When I first hit these chapters I fully expected for him to provide his own views on these topics and either denounce or support them especially since he himself is a homosexual. However, he avoided that. He made some interesting observations such as the differences in sizes in regions of the brain between homosexuals and straight or that homosexuals tend to be left handed (although I don't fully believe that warrants any further research as I think that's sheer coincidence). Transsexuality isn't exactly talked about much, which is probably because there isn't a lot of research completed on it, but he does mention a potential disorder that may be responsible for it.

Recommendation:
Simply put, this book is a must read if anyone is interested as to the basis and biological happenings that occur during sex. LeVay finds a very happy medium in being simple, yet detailed enough in his topics. The topics he reviewed covered a wide range, which all were very interesting. He presents his own theories, which is great. Also, he does not spend too much time on one topic, which keeps the flow of the reader going and not fixated on a certain topic for too long. For someone who does not read books often (or at all), I found myself able to read through this book with relative ease. That's not to say that this book shouldn't be read by neurologists as it's too dumbed down as the ideas he presents are unique and novel. Anyone can read this book and should.