To be clear, I'm talking about kids before puberty and with body curiosity. They understood all the usual red lights around adults and anything coercive.
If they're OK with (mutual) exploration of the 'doctors and nurses' type which was nothing out of the ordinary in my UK childhood 60 years ago I'm not going to stop them or make them feel guilty or ashamed.
We had one that came back and bit us...
DD and a friend (girl) who met at with their Mothers a Tumble Tots were, and remain, best buddies. Aged 6 or 7 they'd been dressing up at friends house and took pictures using one of those disposable cameras that were a thing before mobile phones etc. For some reason they then thought it would be funny to take pictures of each other in the all together.
Camera then got shoved in a drawer and forgotten about for close to ten years. It was found during a clear out, along with a couple of others, and dropped of at Boots to be developed.
First we know is a call from friend's Mum insisting my DP and DD come to her hose immediately. Boots, finding pictures of young girls capering about in the buff reported it to the police.
Both girls, by now 15ish, were massively embarrassed. Both were spoken to by a female police officer and gave consistent accounts as to where/when. The approx timing was clear as it was when the friend's family were in temp accom they occupied for less than year. Nothing further came of it.