American scientists have managed to manipulate the brain of a female mouse to express characteristics more similar to that of a male by injecting an enzyme. Scientists from the University of Maryland have been researching the developments in newborn mice's brains. In order to change the DNA of the area in the brain which plays an effective role in determining gender, scientists injected an enzyme called DNMT into female mice. Although the mice are physically female, it was reported that they showed characteristics of male behavior. Bridget Nugent, one of the scientists who conducted the research project, stressed that they broke new ground as it was believed that scientists could not interfere with the gender of living beings after they were born. Scientist who observed which hormones and cells play a role during the "male-zation" process said that the microglia cells, the basic organisms that build the immune system, release a component called "prostaglandin." The study by the American scientists also drew attention to the effect of DNMT enzymes in the immune system and the determination of gender. The results of the study have been published in the science magazine Nature Neuroscience. It was already known that the male and female characteristics of the human brain as well as the brains of animals is developed in the mother's womb, and male and female brains do not have the same mass. However, there was a very little information about how this development occurs.