In 2002, evolutionary biologist Jenny Graves shared a controversial calculation . The human Y chromosome, she wrote two years later in a commentary, "is running out of time." The male-determining sex chromosome has lost 97 percent of its ancestral genes in the last 300 million years. If that rate continues, Graves calculated, it could vanish in several million more. The doomed fate of the Y chromosome quickly took the media by storm, in many cases without the nuance Graves had intended. Her