I've noticed the BO for a few months now - it's really 'masculine' smelling - not like a little boy at all!
Tonight at bathtime he was showing me that he has hairy testicles - and he has! Just fine, fair, downy hair. He is also quite 'developed' down there, and seems to get quite frequent erections.
DS1 (11) is nowhere near as developed-looking 
Anything to worry about, or just normal, do you think?
He's tall for his age, but not otherwise mature in any way - quite immature socially really, in fact....