The effect of sunscreen on the development of nevi and melanotic nevi which can potentially turn into melanomas is not properly understood and needs to be investigated. It has been reported in the oxford journals also.
I sincerely hope that helps. Take care and regards.
thankyou very much for your response and for the reference to the oxford journals they have provided some interesting reading.
I guess until there is a more definative conclusions the only sensible thing I can do is to add elements of sun avoidance (within reason dont want to avoid to such an extent I get a vitamin D problem) and wearing more protective clothing to continued sunscreen use where neither of the previous 2 options is sufficient.
Any other comments are also welcome but thankyou once again for your reply it was most helpful.
Thank you for yoour kind words. I am glad i could be of help. Take care and regards.