James Watson, co-identifier of DNA back in 1953, is trying to push the Gattaca game by blaming "stupidity," an adjective not necessarily describing definitive learning handicaps, on bum genes.
"Stupidity" has always been a fairly relative term: it's quite a mistake to attribute a lack of common sense to low cognitive abilities (if that's even how Watson intends the word to be understood). I know quite a few people who weren't college material who, while not in the intellectual realm for discussing theories and principles, are solidly capable of completing a lifelong series of reasoned decisions.
By the same token, I've seen veritable Mensa candidates who would most likely need parental supervision beyond the age of 45.
Watson tips his hand when, later on in the article, he remarks about how grand and ethically benign it would be to make all girls "beautiful"; as if there's a comeliness standard outside the horrid annals of the Jungmadelbund.
Confusing subjective preferences and kooky visions with speculative science is a reliable indication that a scientist may need to undertake the transition from laboratory to rest home.