Naturist clubs attract more men than women (for various reasons, see later), and many cope by becoming a GatedCommunity and requiring that there must be the same number of males as females - consequently, they have waiting lists of unaccompanied men. If a naturist club failed to take this into account at all (e.g. if it was "gender-blind"), then it might well be considered inherently discriminatory.
Becoming a GatedCommunity is a good example of trying to fix the imbalance in the wrong way. If you want to read a lot more about why women do and do not join Naturist clubs, you should read the extensive list from the [Young Naturists] society, which is best edited list I've come across. The most concise representation I've seen is [1]. In general, it has more to do with body image than it does to do with perceptions of insecurity, especially since all heterosexual naturists clubs are paranoid about any sexual activity, and highly intolerant of sexual feelings. (Queer clubs and naturist night clubs are different environments though.) Some clubs do have a limit on single men, but I'm fairly sure that is an AntiPattern because there is no evidence to suggest that women are equally as likely to be naturists as men. Indeed, there is little sociological evidence about naturism in the first place. You will find that many naturist clubs are just as eager to get women out as OnlineCommunities for programmers. It may be a similar phenomenon to Wiki:OrphansPreferred where gender-biases are self-perpetuating. It's no secret that women prefer to be around women, not a heavily male-dominated environment, which is a likely reason why most women naturists enter the subculture through either their parents or with their boyfriend, girlfriend (very rare), or husband as they have a social network they can relate to. However, at BurningMan, the same number of women as men seem to go nude, perhaps because the environment is inherently gender-neutral (across all genders, male, female, and queer). And the Ann Arbor naked mile run is fairly mixed, although not 50/50. Of course, there is no good sociological data on Naturism (the NaturismParadox?).
PerceptionOfVulnerability is a factor in female involvement: one page cites "reasonable (though unfounded) worries about physical safety" as one reason for a reduced female presence. Note that despite the paranoia of naturist clubs against harassment, that hasn't been sufficient to get women to join. Safety is merely a hygiene factor (cf. Frederick Herzberg's Motivator-Hygiene theory), inasmuch as women are always hesitant to enter any male-dominated environment for fear or annoyance of being hit on. Thus a lack of safety will drive women (and men) away, but the presence of safety is generally not in itself a reason to join.
Wikis have a similar PerceptionOfVulnerability problem to naturist clubs. So try to make your wiki feel safer - remove personal attacks and flame wars, act as a community against harassment, actively intervene. This is not sufficient, but it is necessary.
ed: I'm feeling overly risqué with even admitting that I'm reading about this, but I've kind of decided that since child pornography is the backdoor key to the limitations of free speech, I'm going to have to read about it somehow, and naturism is an innocuous case. Plus, naturists form a subculture on the Internet that is interesting to study, as demonstrated above regarding gender roles. -- SunirShah (signed for culpability)
Following through on this is seriously not safe for work and LIKELY ILLEGAL IN YOUR COUNTRY, but I'll give you a link to MetaFilter which talks about the link I'm commenting on. This will be the closest MeatballWiki will ever come to child pornography. MetaFilter gives a [run down] on probably the worst abuse of naturism as quasi-pornography on the Internet (at least as discoverable through "legitimate" channels). I understand that nudism does LimitTemptation [2], and thus is not pornography, but that video distributor is atrociously exploitive even if it currently is legal. What is speaks of is the degradation of the integrity of people's moral rights (qua LifeInText), as it is likely it was some jerk who sold the videotapes of these private events to make some cash. Not many parents would consent to having their children videotaped nude if they knew someone else was going to resell those tapes for $60 USD a copy (implicitly to fetishists), and those that do need a pretty good excuse for doing so.
There are also missing discussions of psychological distance between the viewer and the photographed. While we accept nude pictures of children in tribal societies that go nude in such magazines as National Geographic, even if there are many stories of these images being subverted into pornography by teenage boys in the days before the Internet, we find it difficult to accept pictures of similar societies that look like us (i.e. rich and white), because we can relate to them and relate them to porn, sexual fantasies, our neighbours whom we have crushes on, and so on. Although, there is some who believe that National Geographic routinely included pictures of naked women for the secondary effect of attracting horny men, nonetheless the images are non-sexual depictions of nude children which declassifies them as child pornography, even if they are being sold indirectly as soft-core pornography to paedophiles.
Does this, though, speak for a need of stronger protections than copyright? I am sceptical of all ploys to use "kiddie porn" as an excuse to reduce civil liberties, but I am also not so naive. The Internet has exploded the rate and intensity of the child porn industry. As the John Robin Sharpe child pornography ruling has reset the laws [3], at least in Canada we're playing games with how we limit speech around this contentious issue. Should we limit naturists? No. Should we limit reselling their videos as quasi-porn? Probably, but how, I don't know. -- SunirShah (signed for culpability)
The question is always where does ones own freedom start to curtail other peoples freedoms? Therefore I think the point is to not to limit the video reselling in itself, but the degrading conduct with other peoples private lives. -- DavidSchmitt
What's really disturbing is that we are getting ~20 unique visitors a day to this page looking for child pornography, which is more than most flame wars get around here. Thus, this page is NotIndexed. -- SunirShah
See also: WikiPedia:internet_child_pornography.