If they are already dedicated to service, whether they are a guy or a girl, they are already committed to doing the job. I'm a member of a co-ed service fraternity, and there are no differences that I see. When it comes to volunteering, I think that both men and women are eager to help in whatever way possible. I have noticed that women are more self-motivated, whereas men tend to motivated each other toward volunteer work.
Men choose physical labor as compared to women who take more 'caring' jobs.
Men are more likely to go work for Habitat for Humanity, and women are more likely to volunteer at retirement facilities.