Interesting perspective, but do you think she would not have made girl friends when the kids split like that had she not be in scouts? (not knocking Girl Scouts by the way, I love it).
DS was my kid whose friends were all of the opposite gender as a younger kid. He loved dancing and by second grade was at the studio 4 three nights a week (would have been more if we had had the time and money) and was usually the only boy in his classes and he just tended to hang out with and befriend girls from preschool onwards.
I remember my father in law demanding of him (when he was about 7) why all of his friends were girls. I cringed at the question and its tone but was delighted to find out that DS not only had an answer, but it was pretty perceptive: he explained that whenever a bunch of boys said they'd play knights they grabbed swords and started beating each other up with them but when the girls played knights they could spend hours running through the forest tailing long and interesting stories. He liked stories a lot and didn't really like beating people up.
Anyway, as he got older, he found more and more boys who also liked stories and other things he enjoyed and now at 16 nearly all of his friends are boys (he has one close female friend from his childhood years--we no longer live near her, but they keep in touch). He had no trouble finding and bonding with other boys who shared similar interests as he got older and the kids sorted themselves more by interest than just age and gender.