I am curious. Has there been any testing of tanning that can be deemed accurate.

I've done 23&me, per that site none of my easy to tan close relatives should tan.

I myself am fair but posses more Spanish/Portuguese DNA (accurate to ancestry as that'd also include Basque) than my sibling. About half the parent who has that ancestry and the sibling are about a quarter. But they tan and I do not. In fact I can burn badly as exemplified this weekend despite sunscreen.