I do TKD right now and did karate for many years before then. I am all about the white underwear, so no problem. When I did karate a lot of women wore non-padded biking pants for some reason underneath their Gis. At TKD, I notice women and men wearing all manner of underwear beneath their uniforms. I think after awhile you give up worrying about the see-throughness of the uniform. Anyway, the top covers a lot of the ass, so you have to look hard to notice.