Rowan Hooper reports in Wired that researchers at Duke University’s Institute for Genome Sciences and Policy are concluding the human genome is actually two different genomes, one male and one female:

Women (and all female mammals) have two copies of the X chromosome, but the extra copy isn’t needed, and is switched off in a process called X inactivation. Or that’s what scientists thought.
“Our study shows that the inactive X in women is not as silent as we thought,” said co-author Laura Carrel, a molecular biologist at Penn State College of Medicine, in Hershey, Pennsylvania. “The effects of these genes from the inactive X chromosome could explain some of the differences between men and women that aren’t attributable to sex hormones.”