Sex differences determined not simply by gender

Sex differences determined not simply by gender. Scientists have uncovered an inherent difference in the way the genes of males or females can be "switched off" or silenced in the body's developing immune system. Adapted from a media release issued by the Medical Research Council Monday 13 September 2010 Researchers at Imperial College London have uncovered an inherent difference in the way the genes of males or females can be "switched off" or silenced in the body's developing immune system. This finding will have a significant impact on the way researchers approach diseases that have a disproportionate effect on one sex over the other, such as lupus, rheumatoid arthritis or multiple sclerosis, which all occur more frequently in women than men. The results of the study show that the sex chromosomes, XY in males and XX in females, have a highly significant influence on how hundreds of genes behave in males and females. Distinguishing characteristics between males and females, such as face shape or body outline are often been put down to either differences in development or hormones. The research team, based at the MRC Clinical Sciences Centre , found that more genes were switched off or "silenced" in males rather than females.