I also think (and some may find this controversial) that younger girls (under 10s) should get some vitamin D through sun exposure before the age where they have to cover up. I mean little things like wearing short sleeves when they go out in Spring, wearing 3/4 length skirts or dresses. I read somewhere that such a young age is the optimum time for absorption of vitamin D anyway. Of course this has to be done carefully as well because too much exposure can cause sunburn or other skin damage, but a healthy manageable amount of exposure is good and helps prevent diseases as well. I personally am quite distrustful of sunblock. My Dr says they can block beneficial UV, not just harmful UV, but at the same time I’m not oblivious to the dangers of excessive sun exposure either so it’s a balancing act but I am convinced that exposure at a young age (that the child can tolerate and doesn’t cause heat rash or sunburn) is healthy.
The length of time depends on the child as some kids can play outside for hours with no problems and some get sunburn within ten minutes. Avoid high noon strong summer sun as that’s often more damaging, but morning sun in summer or afternoon sun in spring tends to be more manageable. You’ll know your own child and how much time is appropriate for her (boys don’t have to worry as much as they can easily get sun exposure when they’re older anyway)./