What do you think of women-only karate classes? I've met a few women, in other styles, who only started martial arts training because they were able to try it in a women's only class. If you search on the web, you find several karate schools that have some classes for women-only as an offering amongst their many classes. There are a handful of dojos that are entirely women-only. The common points that are highlighted include being a safe space with understanding, encouragement, focus on individual progress, being without concern or attention to body image in a group, and desirable for certain personal or religious reasons.
I think it is an interesting thing to consider; does creating a kind, gentle, supportive space to learn karate detract from the value, purpose, efficacy, or spirit of martial arts training? Can a woman get adequate training in a women's only class? Can a women's only class be a bridge to a coed class for women who might never otherwise consider training? If you extend this further, more interesting questions arise: if you consider that some women might have religious reasons that exclude training with men in the same class, you may be speaking about women who usually wear a hijab (head scarf) or chador (full-length black covering) in public. Have you been in a karate class with a student wearing a head scarf? Is this an issue?

In Iran, Shitoryu Shukohai Union style was banned from the Iran Karate Federation in 2009 after young Iranian women competed in Germany at a World Championship without wearing their hijab. They were told they could not compete if they insisted on wearing them. The removed them and competed. When they returned home, their style was banned and it was said, "they should be punished."
http://www.astreetjournalist.com/2009/12/22/irans-karate-federation-bans-womens-shukokai-style-due-to-hijab-unveiling/ In 2011, hijab were allowed in the Asian Karate Games
Here's a YouTube video about a karate school for girls in Tehran, Iran.
http://www.youtube.com/watch?v=qo8euChlyzM Any thoughts or comments?