ChesterJohn, yes - men are diagnosed with fibro, but it's a rare event.
One of the issues with these auto-immune diseases is that it's a process of elimination to determine precisely what's going on. For some of these conditions, there are definitive tests that can be performed to determine what it is. There is no labwork or blood test for fibromyalgia - it is only identified through a process of elimination. And, since there's no true "test" that can confirm or refute the diagnosis, patients often spend decades searching for answers and a proper diagnosis. During that time, they are misprescribed medications, over-medicated, and experience extreme frustration.
Lupus, for instance, tends to mimic the symptoms of other diseases and there's even a definitive blood test that will identify "markers" that correlate with the disease. However, these "markers" don't necessarily mean that a person that is experiencing symptoms actually has Lupus. Rheumatoid Arthritis also has very specific "markers" but people are often misdiagnosed by rheumatologists because it takes months to get in to see a rheumatologist, and the patient is given a clean bill of health if they aren't in the middle of a rheumatic flare. Yes, the inflammation levels are slightly elevated, but not enough to "diagnose" RA.
It's all a very confounding matter for people who are suffering.