Even though statistics show that women have higher incidences of anxiety and mood disorders, they also experience greater happiness compared to men. Nobody has ever understood what the basis for this is — barring the theories of notable best sellers touting the planetary origins of the genders, that is.MORE FROM MNN: Stay Safe and Happy When You Travel SoloBut now a new gene has been identified that appears to make females, but not men, happy. Researchers at the University of South Florida, Columbia University, and the New York State Psychiatry Institute reveal the findings of the study in Progress in Neuro-Psychopharmacology & Biological Psychiatry.The scientists found that the low-expression of the gene MAOA (monoamine oxidase A) is associated with higher levels of happiness in women. They were not able to find such a link in men.The MAOA gene works much like many antidepressants by targeting the enzyme that breaks down the same neurotransmitters that many antidepressants target.MORE FROM MNN: Is Prozac Poisoning the Great Lakes?Lead author, Henian Chen, MD, PhD, said, “This is the first happiness gene for women. I was surprised by the result, because low expression of MAOA has been related to some negative outcomes … but, at least for women, our study points to a brighter side of this gene.”Chen and the researchers collected and analyzed data from 193 women and 152 men who had all participated in a longitudinal mental health study called “Children in the Community.” Their DNA had been studied for MAOA gene variation, and then a widely used scale was used to determine happiness scores.The results revealed that women with the low-expression type of MAOA were much happier than women with no such copies. Women with one copy scored higher, and those with two copies higher still. A similar number of males had the happy-boosting MAOA, yet they did not report any higher happiness levels compared to the other men. The gene does not seem to make men any happier.Chen believes this new finding might help explain the difference between men and women, and provide a deeper understanding of how specific genes affect happiness.MORE FROM MNN: Keep Your Pets Healthy, Happy This Summer