This is a book full of overturned expectations, not the least of which concerns the gender of its authors. That they are indisputably male is attested to not only by their names but also by the stylishness of the beards they sport on their dust-jacket photos. Yet so close do Jeremy Cherfas and John Gribbin come to banishing the male half of the human race to superfluity that one might have sworn they were militant feminists on a crusade. Which is to say that they very nearly answer the question posed by their subtitle with an emasculating "Yes."

An alternative way of posing that question is to ask, with the authors, "Why do women bother to have sons?" Now that the cloning of a human being has moved beyond the realm of science fiction, now that we are "dramatically close to the day when it may be possible to use gametes -- egg cells -- from two distinct female individuals and persuade them to fuse into a viable, sexually produced zygote, thus getting the benefits of sex without the hassles of gender," what is the point of maleness? After all, plants like the dandelion and fishes like the Amazon molly flourish by asexual reproduction.

The stock answer to such questions has been to point out that it is the recombination of genetic material that distinguishes sexual from asexual reproduction and that sexual species tend to evolve faster than asexual ones. This speediness, in turn, allows sexual species to adapt readily to changes in their ecosystems.

In one of several assaults on received wisdom, the authors brand this argument as no longer decisive for the human species. Why? "Mankind has conquered the environment to an enormous degree, making the variety possible through sexual reproduction largely redundant. When a new Ice Age comes along, the successful members of our species won't be the ones with more hair, or more fat, but the ones with the most efficient technology to keep them warm." Given that in general mothers take far more care of their children than fathers do, the authors continue to wonder whether the race would not do better -- that is, propagate more efficiently -- if it consisted of females alone.

Before disclosing Cherfas and Gribbin's eleventh-hour rescue of the male ego, I want to wander down some of the alluring byways they take en route to it. It is wonderful to learn, for example, that there is a species of turtle and another of alligator for which gender is determined by temperature. At 26 degrees Celsius all the turtle eggs hatch as males, at 34 degrees, all as females; at about 30 degrees equal numbers of each sex will hatch. For the Mississippi alligator the temperature-gender correlation is just the reverse. In a flight of shrewd fancy, the authors suggest that dinosaurs might also have been subject to such a climatic lottery, with an untoward change in the Earth's temperature leaving a doomed collection of bachelors or bachelorettes.

And here is something all of us have been pondering: Do males' orgasms feel different from females'? In the mid -- 1970s experimenters enlisted a number of students to write descriptions of their ecstasies, deleted telltale words like "penis," and asked another group to identify the author of each purple passage as either male or female. None of the latter group "could discriminate between male and female descriptions of orgasm . . . This result suggests that the experience of orgasm is very similar indeed in men and women."

But I have kept the suspense key depressed too long. In the book's last 20 pages, the authors find a good word to say for sexual reproduction -- and hence human males -- provided that the concept of environment is broadened to include pathogens, the technical word for germs. These microorganisms, Cherfas and Gribbin point out, are whizzes at rapid-fire adaptation, but the random genetic recombination provided by sexual reproduction gives human beings a distinct advantage in the effort "to keep one step ahead of the invaders." The human male, then, remains important in procreation largely because of his contribution to human immunity, and sex itself can be viewed as a preventive health maneuver.

"The Redundant Male" is a book with something for almost everyone but moral majoritarians. For fans of first-rate science writing, there is a parade of elegant argumentation and lucid prose. (One caveat is in order, though: Chapter 1, which details the inner workings of cells and recombinant DNA, is rough sledding.) For women there is confirmation of the power they have been accumulating in recent years, as well as such heartening asides as this: The largest living creatures ever are lady blue whales. For males there is, in the rehabilitation of their role in sexual reproduction, reason to believe they have a place in procreation after all.