Gay, Straight, and the Reason Why: The Science of Sexual Orientation [Paperback]

This is the book we've been waiting for: a clear, readable, and intelligent review of the science to-date around homosexuality. Simon LeVay ran the groundbreaking study that found a correlation between body structures and sexual orientation, and although his early study was superseded by a lot of other research, he clearly remains an expert on the subject. Science has generated a lot of powerful evidence over the last few decades, reported piecemeal in the popular press, but only now has someone of Mr. LeVay's caliber pulled all this knowledge together into one place.

"Gay, Straight, and the Reasons Why" achieves two things: First, it describes the science in understandable language. Given the complexity of genetics, hormones, body structures, and sexuality, that alone is impressive. Second, he achieves the more important task of putting these studies in context, explaining the relevance of each data set in our overall understanding of the relationships between human physiology and behavior.

While religions and politicians argue endlessly about homosexuality and gay rights, those of us in the reality-based community need facts. LeVay is not claiming we now understand everything that needs knowing, he's explaining the evidence we do have. That makes this book an important, even essential, contribution to the discussion. The critic here who says this is discredited by Kinsey's research or an out of print book from 1971 is speaking from some old mindset that doesn't apply. If you want to understand the current state of research into the genetic and physical origins of homosexuality, buy and read this book. Highest recommendation.

Simon LeVay is a retired scientist. He is also gay. So you can expect his approach to be rational and sympathetic toward the question of homosexuality.

I had been familiar with most of the arguments and evidence. I have had a little direct background too. I conducted experiments in 1968 as an undergraduate physiological psychology student to try to induce homosexuality in rats. I failed for reasons which I didn't understand then but LeVay's book helps explain.

LeVay's great study was twenty years ago shortly before he retired. He found that two nuclei in the hypothalamus were of different sizes in the different sexes and that the male homosexuals brains were similar to the pattern of heterosexual women. This was a big discovery at the time and it remains an important finding. This finding has been confirmed in other studies but has not had the kind of follow up that you might have expected.

That's a consistent pattern - suggestive observations but no follow up. Apparently the political climate makes homosexual studies too controversial. Gay activists in general oppose the idea that their homosexuality is a choice, but many also seem to oppose the idea that it is biological either. Some of the comments in this thread make bitter attacks on LeVay. LeVay seems to be a mild mannered, polite and reasonable person. The kind of person you might like to meet. He spent much if not most of his career studying these questions. He knows what he's talking about.

However he does leave out some issues. I expected to see some references to the work of Steve Sailor, Gregory Cochran, Henry Harpending, and Paul Ewald. None. LeVay presents enough evidence to convince almost anyone except gay ideologues and the religiously commited that homosexuality is a developmental disease having to do with the amount and timing of testosterone prenatally. He does not go after the question as to what causes these amount and timing anomalies. So for what he covers, LeVay is very persuasive. But he doesn't go into some of the other open questions.

LeVay is even handed in his discussions of arguments and theories. For many theories he makes a case for it and then expresses his opinion. After a while you begin to notice that the evidence is never very compelling. Most of the observations and theories are really just unexamined speculations. For example the older brother theory posits that some kind of Rh-like immunicological effect is working. I first heard this theory at least a decade ago but it remasins just a possibility. In Rh immunicological disease the antigens can be seen and measured. The mechanism is well established, yet there is no similar empirical evidence for the proposed older brother effect. It remains just an early speculation.

At least half of all the suggested mechanisms discussed by LeVay as possibly leading to homosexuality have very ambiguous evidence. This isn't LeVay's fault. It seems to be the nature of the whole research area. Initial findings are not pursued. Ideas are discussed for years as ideas without much attempt verify or falsify. Some of this can be understood as the result of the fact that many differentiating observations are small. For example, LeVay discusses 'gaydar' - those features that allow someone to spot a gay person. Almost all of these signs are small and ambiguous. For example gay men are smaller and slighter than straight men - but not very much. So you would be very wrong to classify all men who box as bantamweights as gay. Similarly the differential length of digits is a tendency not a reliable indicator.

In fact LeVay's observation of the differences in male-female and straight-gay brains is just about the only measurement that seems solid. All the others are rather shaky. I would have expected that more progress would have been made by now. Homosexuality still has many areas of mystery but I suspect that it is reluctance and resistance that accounts for the sad state of knowledge. LeVay seems to be the most even handed and honest of the writers on this subject.

I enjoyed this book, and I would recommend to everyone I know to read it. This book is useful and important because the majority of people are at best in the dark about what it means to be gay, at worst homophobes. I did not hesitate about buying this book: I don't know any gays personally, and I've always wondered what makes someone gay. All the false and naive ideas I had (and I had more than I realized) were certainly cleared up by this book. This is important reading, because it gives the average person real evidence to combat the dangerous notions spread by homophobes. Since these false ideas and the discrimination they engender cause considerable suffering in our society today, I think it is important for people to read a book such as this one, which considers the origins of homosexuality from a scientific viewpoint. These are indeed firm arguments put forward, which are difficult to refute considering the volume of supportive data. In conclusion, one comes away from this book convinced that sexual orientation is a biologically controlled characteristic as natural as variation in eye color or height.
One would expect the author to be biased, since he quickly declares he is gay himself, but I had the overall impression that he carefully considers the available data and does not push any ideas that are not fully supported by experimental data. Since I am a scientist myself, I appreciated his cautious approach and his consideration of competing ideas.
I have a few criticisms, however: the fact that this book targets a general audience is no excuse to have omitted error bars on the figures and citations of the sample sizes. It gets a little long and technical at points, and there is perhaps not much interest in mentioning studies for which the results are not conclusive. There are unfortunately several typographical errors that sometimes even make the meaning of the sentence unclear. Why didn't the editors do their job a little better on such an important book?