Twin Cohort undifferentiated
I note that though this study appears to have a fairly large cohort
of twins it fails to differentiate between mono-zygotic ( identical) and
di-zygotic (unidentical)twins in the cohort. Given that IQ has been highly
associated with genes I deem this lack of differentiation a flaw of the
study.The fact that there was no mention of controlling for this important
confounder is in my opinion another weakness.
It would have been interesting to see the results of the IQs of
singletons compared with an identical twin cohort and an unidentical twin
cohort independently rather than comparism with a mixed bag cohort of
Taiwo Ajayi is himself one of a pair of Mono-zygotic Twins.
Competing interests: No competing interests