In most sports, guys and girls wear the same type of uniform that looks the same. However, in some sports, guys would just look weird if they wore the girls' uniforms. One sport that always sticks out in my mind is volleyball and sometimes cheerleading.
Volleyball sticks out in my mind because it would just look weird having a guy in spandex shorts. It think it's very important for guys to have different uniforms than the girls. I just think you should completely differ the two and give them different uniforms so they can have their originality. For example, in basketball guys and girls both have those long baggy shorts, and for the most part we know the girls are wishing they had some shorter shorts to wear. It may be harder to find men's volleyball uniforms in stores, but it should be just as easy to find them in catalogs or on websites just like women's uniforms. If you are having trouble finding uniforms even though you shouldn't, you can always just start calling around and you'll eventually find them somewhere.
If you're team has the money, you can purchase volleyball practice uniforms for both men and women. Also, to go with the men's volleyball uniforms, you can purchase adidas volleyball socks or any brand to go with your outfit. However, it's not too often though that you see guys in high socks, that may be one thing the girls will wear, but not the guys!