I disagree BeerTricksPotter with that they are born not made.
I am very much not a girly girl - no matter how much my mother and elder sisters wanted me to be, as a child I wore wellington boots and dungarees as I wanted to be a farmer, and that's how I thought I would be a farmer, no matter how pretty a dress my mother put on me she would find me mucking out the neighbours horses, rolling around in the hay barn, in the silos, in building sand on my dad's building sites.
I've never worn makeup, and will often leave the house, hastily running a hairbrush through my hair. I always wear trousers, and will never be found in skirts or dresses.
However, my dds despite having this as their roll model, from a very young age, wanted glitter in their hair, learnt to plait their own hair, as I was unable to do it, at 4, I caught my eldest smuggling lip gloss to school, as she 'didn't want to be seen without her makeup on'.
I have no craft, cookery, sewing, art ability in my body, either talent or inclination, the girls are so good at these skills, more than once I've been asked whether I had done the work for them, I had to assure the teacher, believe me that if I had done the work, no way would it of been up to that standard.
This is most certainly not nurtre and I believe is 100% nature.
My son on the other hand, has had these girls as well as my dh and I as his role models, and no matter how much persuasion they would get him to sit down and do art and craft with them, do cookery, be part of their tea parties, have his hair styled with gel.
You have a boy who would take himself away from the girls and play by himself with his cars, trains, work bench.
The older girls had all the electrical gadgets, he would take them (with permission) as they weren't interested, and would figure out on his own how they work, how to program etc.
If there is ever a ball around he'll be found kicking, throwing it, he's set up his own lunchtime football club for his year group this year, because there wasn't one running.
Again 100% nature not nurter.
If scouts are turning into guides due to the female aspect. Then that is a bad thing. If scouts stay as they were, with girls involved then that is less of an issue. But I still think that girls having the option of no boy space, it is unfair and not equality for boys to not have a no girl space option.