Growing up in Britain, I thought that I would have a problem with naked sauna before I tried it. Then I thought naked mixed sauna would be difficult, but when I actually went I did not mind at all. As long as everyone is comfortable then I see no issue.
Once, I went away for a weekend with a group of many nationalities. There were separate saunas, so this was just the women's. I walked to the sauna with an American friend who told me she will wear her costume. I hate the idea of doing this myself, but what ever she is happy with is fine. Several women go to sauna, they are mixed nationalities - Belgian, German, French amongst many others.. and I follow, walk in and find that I am the only naked person in the room. I found this quite shocking - as I think some of them found me

Anyway, I just sat down and felt happy not to be wearing an uncomfy sweaty costume. It's still surprising when I think back for me, a Brit, being the only one naked amongst a bunch of continental Europeans
I think it's much healthier for kids to grow up less inhibited and ashamed about their bodies and to know that real people don't look like the images in the magazines and on the billboards of nutritionally challenged, airbrushed individuals...