For others it's an expression of their female side. The exact psychological cause is not known but the feelings are deeply rooted. Others long to do the same but the fear of prejudice from society prevents them from doing so, which causes increased stress. Many experience difficulty in finding accepting partners. It's quite possible that someone you know is either.
Transvestitism is primarily a male practice.
This is probably because it is much more acceptible in our society for a woman to don male apparel than it is for a man to dress as a woman. It is not illegal to dress at home or appear in public as a member of the opposite sex. However, you can become a target of discrimination. In some cases when reasonable discussion fails, the Ontario Human Rights Commission may be able to help. Gender Mosaic also works with the Ottawa police to help protect your rights.