In this film, gender roles are something that get pushed. The lines of what a man should be and what a woman should be, get twisted and blurred.
At the beginning of the film, Michael is a typical male. He isn't very feminine and he doesn't have many relationships with women other than his 6 year old friend Sandy. The way he talks to or about women isn't very respectful. Hey talks about Sandy like she's a sad little girl that only complains. Until he becomes Dorothy Michaels.
As Dorothy Michael's, Michael is forced to face the daily struggles and hardships of being a woman. Not only physically with the clothing or the makeup, but also emotionally. Dorothy doesn't get the respect he normally does as a man. Like in the film Thelma & Louise, Thelma goes from a fragile, damsel in distress character, to a strong woman. In Michael's case, transforming from a typically male character, to a strong female role model.
Michael doesn't always see things the way he does as Dorothy. Near the end of the film, Michael stops dressing as Dorothy and his life pretty much goes back to the way it was. He may have a slightly larger respect for women but nothing major in his life changes. He goes back to dating women and he continues to be an actor.