Yeah, I'm a woman -- but I like to use men's tee shirts as night shirts. They're more comfortable, they tend to wash better, and, let's face it, they're usually MUCH less expensive!
I purchased several of these for just that purpose. I usually purchase them at least 3-4 sizes larger than my normal "daytime" size and they work perfectly as nightshirts - large enough not to bind, long enough to cover the essentials, really perfect. And I'm almost 5'9" tall.