Malcolm Pottsis the Fred H. Bixby Professor of population and family planning at the University of California–Berkeley. He has worked internationally as an obstetrician and a research scientist for four decades. He is the author ofQueen Victoria’s GeneandEver Since Adam and Eve: The Evolution of Human Sexuality.He lives in Berkeley, California.Thomas Haydenis a freelance journalist and writer with a special interest in science, medicine, and culture. Formerly a staff writer atNewsweekandU.S. News & World Report, his articles and reviews have appeared inNational Geographic,Nature, andThe Washington Post. He is the coauthor ofOn Call in Hell: A Doctor's Iraq War Story. He lives in San Francisco.