As a rule, I would side with Lucky and Lighthouse on this subject. That was before seeing how most of the girls in my church's youth group dress for Wednesday night services. Year-round, you walk in and see girls aged 14 to 18 wearing short shorts, micro-mini skirts, belly shirts, and extremely tight clothing. I'd say that out of the 45 kids in the youth group, a little less than half are girls. And, out of those (give or take) 20 girls, 5 (including my daughter) do not dress to advertise their bodies. Those 5 girls generally wear blue jeans or skirts to their knees (or lower) and big shirts. My daughter tends to wear her favorite blue jeans with paint all over them and one of the t-shirts I've given her because I don't wear it anymore.
The youth pastor's wife complained about what my daughter wears to youth group. I called the pastor and told him, number one, she's my daughter. If someone doesn't like what she wears, they are to come to me, not her. I pretty much choose her clothes, even though she's 14. And, number two, they should look at these other girls dressing like prostitutes before they complain about my daughter when she's pretty much covered from neck to ankle.
When I was in youth group, it wasn't a social scene. We had Bible study and fellowship every week. Once a month, we had Bible study and pizza at the youth pastor's house. And, once a year, we had a youth Bible camp out, where 50 to 75 teens (both boys and girls) and ten to fifteen married couples would go to the lake and camp out and have Bible study and witnessing in June. We girls were not allowed to wear bikinis or short shorts while at the camp out. And, if we wanted to swim, we had to have one-piece swimsuits with tee-shirt and shorts over them.
Today's youth groups aren't like that, at least not from what I've witnessed in my own church.