What is Sex?

With its eye-catching title and acclaimed mother-and-son team of science writers (What Is Life?), this look at something that everyone talks about but few understand promises much--but delivers somewhat less. Discussion of the behavioral aspects of sex among the higher animals is limited in favor of a biologist's-eye treatment (Margulis is a professor of biology at the University of Massachusetts) of sex as an exchange of energy and genetic information. We thus learn much about the diversity of damselfly penises, about female whiptale lizards that can reproduce uniparentally and about Myxomycotes, which ""endure the removal of large sections of their plasmodia,"" but little about the way sex plays out in our cultures or in the behaviors of other large mammals. Homosexuality, while considered, is largely side-stepped, aside from a few extreme anecdotal cases like that of Emma, a woman with a penis-sized clitoris and a vagina. The connection between sex and death is reconfigured, meanwhile, as a connection between reproduction and cell death. The 80 full-color photos (some seen by PW), both page sized and bite sized, do much to enhance the allure of the book, however, as do the authors' sometimes poetic sensibilities (""The Universe is a swelter of starlight, swamped in excess, consumed by time,"" reads the book's opening). Ultimately, though, Margulis and Sagan never satisfactorily answer the titular question, and in fact raise more questions than their focus on our microbial origins answers. (Nov.)