In English, "male nurse" has a slightly pejorative sound to it. By going out of the way to point out that a man is taking a job traditionally held by women, it seems there's a subtle hint that he's less than manly.
Generally, I'm in favor of gender-neutral job titles. Mail carrier vs. mailman, police officer vs. policeman, etc. Sometimes they get kind of awkward, like "chairperson," but so be it. ("Fisherman" is a really tough one -- the only possible substitute I've ever heard is "angler," but that's not a very familiar term.)
When I waited tables in college, it was fashionable to call us "waitrons," which we liked because it was not only gender-neutral but captured the occasionally dehumanizing robotic feeling to the job.