clothing items do not have any specific gender or sexuality attached to them. it is simply a piece of cloth, in various shapes, used to cover the body. Our cultures attach meaning to these pieces of cloth and often use them as sex-and-gender signifiers.
two babies basicly look the same. you put one in pink pjs and one in blue, there's a cultural assumption that pink=girl and blue=boy. interestingly enough, in the late 1800s, the opposite would have been true. pink, being a derivative of red or in the red family, was considered a 'power' color and therefore a signifier of boys. Blue, being a color that is calm and soothing which is a trait considered feminine, would signify a girl.
skirts or skirt-like shapes are also cross sexual. kilts, sarongs, and variations still exist in many cultures and are worn by men (in some cases, exclusively). they are considered masculine garments. There isn't much difference between my cargo kilt and my plaid kilt in cut. my husband can wear my plaid kilt (or could, if it were the right size), but our culture doesn't allow him to wear my cargo kilt because it's not 'traditional' and therefore 'not masculine.'
shoes, clothing, make up, nail polish, hair coloring, hair length--none of these things has particular, or inherent, meaning. Throughout time, men and women have worn wigs, make up, all manner of clothing (including pant-like on women and skirt-like on men) in all manner of colors, and all manner of shoes (originally, high heels were for men only). Different cultures, at different times, have assigned different meanings to certain clothing items. Women who were 'mens' items were considered deviant; men who wore 'womens' items were considered deviant. But, it isn't the items themselves, but rather the meaning attached to the items that made people 'normal' or 'deviant.'
many people like to assign a particular sexual meaning to an object. He wears women's clothing because of sexual confusion, fetish, or sexual need/desire. It could be that he simply finds this particular item of clothing a more comfortable expression of who he is. Men who wear eyeliner are not often trying to be women, anymore than they're trying to be rock stars. perhaps they feel that they look good that way, that it expresses who they are. And besides, i think it's sexy. Nail polish too, and long hair, and skirts, and high heel shoes, and whatever else.
People should be free to express themselves. clothing, hair, shoes, makeup, colors--these are ways of expressing oneself to the world. If a man wants to wear a skirt, then he should. it certainly doesnt' mean that he has some strong-sexual urge, fetish, or gender identity problem. It simply means that he prefers it--for a variety of reasons (which may or may not include sexuality, fetish, or gender identity concerns).
i prefer pink camouflage pants. that doesnt' make me a commando, hypermasculine, or a covert operative in fairy land. it simply means i have a preference for the cut and color, i find the fabric fun, and as a socio-political statement, it sort of stands the concept of war on it's head or works against or opposed to the concept of being covert at all (hiding and sneaking around). So, it has the meaning that i give to it, rather than the meaning given to it by our culture.
there's a great first wave feminism writing about women wearing pants. It was a HUGE issue back then. women could be arrested for indecency--particularly if they wore them in public.