Certain groups of people have certain genetic predispositions. Ie when pregnant there is calculation of down syndrome probability, they take your origin into ac

Certain groups of people have certain genetic predispositions. Ie when pregnant there is calculation of down syndrome probability, they take your origin into account. We had something like 1:4000 IIRC, my french teacher who comes from Algeria had 1:200 with his wife. Alcohol tolerance is another (native south americans have lower, as do some asian populations). Over time, env effects also creep up in the genome (ie altitude acclimatization for sherpas). But could be also societal, level of healthcare, level and types of vaccines received and so on.