Oh it's just so hard isn't it? You want to seem fair, you want to be reasonable and you want them to trust and respect you but you also KNOW better than an emotional pubecent teenager.

We wont allow mixed gender sleepovers with friends - except my Godson/nephews etc. My DD is only 9.5 at the moment, but it's just not on. And for good reasons too - Fletch you scare me!!! Although I do think perhaps it's just talk, and although they are talking about sex and stiffies, they don't have the 'follow thru' yet! But it has always been like this - I remember one of the boys in my grade 4 class when I was a kid getting a stiffie in class. The teacher wasnt' in the room at the time but boy did it cause a commotion! So in that respect things haven't changed in 22 years (OMG I feel old!)

Anyway, I'd do your best to explain - like the others have said - Boys can come to the party, but only girls sleep over.