When I take my baby outside, I always cover all of his skin with sunscreen, just as the aap recommends. Isn’t that enough to protect him from cancer and yet give him vitamin d?
No. If you block the rays that burn, you're blocking the rays that help you make vitamin d. Use a vitamin d supplement.
Some what mutually. Exclusive. Human body makes d3 version of vitamin d from ultraviolet exposure to skin and converting a form of cholesterol to vitamin d. If you protect the skin from uv light, skin cannot make vitamin d. If skin cancer is a concern, you can use vitamin d oral supplement in consultation with your doctor.