Yup. My daughters often spend the night with their male cousins, 8 and 6, and all four of them sleep together in the same room. They're just little kids, for goodness' sake.

Still, if their cousins' mom decided that she didn't want her boys in the same room with my girls, I'd honor her request. She has her own views on what's appropriate -- and the same thing goes for your neighbor. Next time you have a sleepover with kids of the opposite sex, have a quick conversation with the parents to hammer out sleeping arrangements so there's no misunderstanding.