I think it's a combination of your flora and genetics. My father's best friend was also his (our) dentist and used to refer to my dad's and grandpa's teeth as "

I think it's a combination of your flora and genetics. My father's best friend was also his (our) dentist and used to refer to my dad's and grandpa's teeth as "the yellow rocks". Men in my family piss stones more than any people I've ever encountered, to the degree that our family folklore includes a highly effective means of dealing with them involving vast amounts of Guinness and tying your genitalia with string. But somehow, our teeth seem to be practically immune to getting cavities. The men in my family are also all strangely averse to sweetened drinks, sugar, candies, desserts, etc; we tend toward the salt, tobacco and whiskey flavor profile. So maybe that kills some of the destructive flora. My mom has 16 fillings; her parents and brother all ended up with false teeth by their 40s. None of my 3 brothers by my father have cavities. It's definitely something that runs on the male lineage, for us at least.