You might inquire of other dermatologists then.
dramatic increase in skin cancer in western world in last 30 yrs, while the 3rd world rates stayed essentially flat.
it has led to two conclusions, both involve sunscreen.
1) sunscreen doenst prevent cancer, it only prevents sunburn, which leads you to spend more time than you should in the sun, bypassing your bodys natural feedback mechanism. IE, because of sunscreen, we spend far more time in sun than we used to.
2) sunscreen actually breaks down into free-radical compounds which attack cells and cause them to become cancerous.
There is absolutely zero arguement by anyone, against the best and safest thing to do being to wear clothing that keep the sun off you.