Let me try asking a few simple questions.
Can you think of any possible problems with having naked
children, pre-pubescent to adolescent, around other naked
teens and adults of both sexes that are not related and that
you don't know?
Do the women not participate for 10-15 days a month?
What makes it necessary to be naked in front of others
rather than privately or as couples instead of groups?
My thoughts afterward, mainly on #3.
1) In my opinion, the most dramatic potential problem for nude youths around nude strangers is sexual abuse.
That's why I specified "
under the watchful eyes of their parents" in post #105 above.
Most (if not all) nude resorts require parents to keep their kids under their supervision at all times, not because the risk of abuse is high (it isn't), but because the kids overall safety is a primary concern. The greatest hazard is probably drowning.
The staff and guests at nude resorts look out for each other in many ways, including kids. For example, our resort has a "Kidsfest" one weekend every June which features 2 days of games and activities for pre-teen kids. On our first Kidsfest a staff member approached me and asked if I had any kids in the Kidsfest. I said yes, and pointed out my two boys. She then explained that non-staff adults were not allowed to observe or participate unless they had kids involved. That's typical. An unknown adult speaking to someone else's kid may be confronted and advised not to do so. However, once the families know each other, everyone relaxes.
I know LOTS of girls & women (and a few males) who have been sexually abused, but NONE of them were the result of nudism.
2) Women are free to participate (or not) as they see fit.
I don't have any statistics, but plenty of women participate regardless of their periods.
Some wear shorts with pads, even though they can't use the pools or hot-tubs with shorts on.
Others use tampons and do all their usual activities while fully nude.
Periods never slowed my wife down...
3) What makes it necessary to sing in the church choir, or serve on church committees, or volunteer for potlucks? Those are group activities, not solitary pursuits.
Why are we advised in Hebrews 10:25 to keep "meeting together" instead of worshipping only in our own homes?
"Necessary" is the wrong word here; "beneficial" or "uplifting" or "inspiring" would be better.
Social nudity brings several benefits:
a) Greater closeness to God - This must sound strange to non-nudist Christians, but it's common for new nudists to feel a greater closeness to God when they're nude. It happened to me the first time (as described in my blog), and still does. I have a friend whom I met here on Christian Forums who used to be a legalistic, moralistic anti-nudist (his own description), who was led by God to begin praying nude at home. It completely changed his outlook, made him more genuine and less legalistic (his own description again), and now he joins my family at the nudist resort for one weekend each summer.
Many will say "I don't need to be nude to get close to God"
That's great, but some people benefit from seeing themselves the way God sees them: stripped of all pretense, unable to hide who they really are, not defined by possessions, just experiencing a genuine relationship.
b) Greater closeness to other people - not in a sexual sense, but again, with more genuineness and even vulnerability, and no pretense. Mind you, I DON'T want to be vulnerable with everyone, but people who become comfortable while nude usually find themselves being much more open with each other. I think it's a very primal understanding of our common humanity, knowing that we are "among our tribe".
c) an important lesson: "the rules of good behavior are the same, with or without clothes".
Almost everyone, especially young adults, benefit from this realization. Being nude isn't carte-blanche to go wild with sex or anything else; it's just...normal life without clothes.
An alternate question would be: What makes it necessary to be clothed in front of others?
If you think it was God clothing Adam & Eve, remember that they were about to be cast into a now-fallen world with "thorns and thistles", wild animals, and cold. They had no idea what to expect, or what to do about it. God, in His grace, made leather clothes for them to deal with their new, hostile environment. Remember, they were the only people on earth at that time. Who was God "hiding their nakedness" from? Each other?
Other reasons people think it's necessary to be clothed in front of others:
"modesty"? (which really means humility, not covering skin)
Why hide what everyone knows about?
morality? What makes it immoral? Temptation? Lust? Those happen with clothes also.
We are to avoid tempting others, but not everyone is tempted by nudity or anything else.
Some religions consider women without head coverings to be "shamefully exposed".
propriety? We are an odd culture: being seen in a swimsuit is OK, but being seen in underwear is taboo (and they both cover the same parts).
When people become comfortable with nudity, they realize all this concern with being covered is nonsense.
legality? Legal prohibitions of nudity have been slipping away for decades.
Roughly half of the U. S. states allow women to be topless in public, as long as they are not committing "lewd acts".