Besides the obvious biological differences between men and women, we differ in many ways, some of which we are not even aware of. How we look and behave is part of our DNA. We have different genes, our brains are wired differently, and we have different hormones. We all know that women have two “X” chromosomes and men have one “X” chromosome and one “Y” chromosome. The X and Y chromosomes determine a person's sex. Chromosomes contain all of the instructions necessary to create a living thing. The male Y chromosome and the female X chromosome are different in size and vary in the number of active genes. The “Our study shows that the inactive X in women is not as silent as we thought,” said Laura Carrel, Ph.D., assistant professor of biochemistry and molecular biology at Penn State College of Medicine, Penn State. Milton S. Hershey Medical Center. . “The effects of these genes on the inactive X chromosome could explain some of the differences between men and women that are not attributable to sex hormones.” A study published in the Journal of Nature in March 2005 discussed X chromosome inactivity. The study indicates that having two active copies of the gene may be of great or very little importance. “Although we showed sex-specific differences, the clinical implications remain unexplored,” Carrel said. "We can conclude, however, that these differences should be recognized as potential factors explaining normal sex differences, but also sex differences in the way certain diseases manifest, progress and respond... middle of article ... ... more similar than we think We all have 46 chromosomes in 23 pairs and only one chromosome differentiates us from being male or female We both share some of the same hormones. So are we really so different? Mahmoud. “Gender Differences: Brain Differences,” M Alagha, April 4, 2011. WebConner, Steve “The hardwired difference between male and female brains could explain why men are “better at reading.” of cards » » The Independent Independent Digital News and. Media, February 3, 2013. Web.DiscoveryHealth.com Writers “Estrogen and Testosterone Hormones Discovery Fit and Health, nd Web.Penn State “Men and Women: The Differences.” reside in the genes. . Web.Swerdloff RS, Wang C. The testis and male sexual function. In: Goldman L, Schafer AI, eds. Cécile Medicine. 24th ed. Philadelphia, PA: Saunders Elsevier; 2011: guys 242.