Identical twins separated at birth in China have almost the same IQs.
A pair of twins grew up to have almost identical IQs despite being raised in different environments
Research at California State University, Fullerton examined the intelligence scores of 15 pairs of identical twins adopted by different families and raised in different environments due to the nation's one-child policy that was implemented between 1980 and 2016.
The twins underwent IQ tests at the age of 11 and again at 14 and comparisons over time proved that the scores were almost identical.
The results could be considered as proof that a person's intelligence is 'set' when they are born instead of being influenced by external factors.
The study authors - led by psychology expert Dr. Nancy Segal - said: "Despite their different homes, educational experiences, and (in some cases) residences in different countries, the twins appear to have interacted with their environments in ways that aligned with their genetic propensities.
"This supports the notion that environments do not act randomly in fashioning developmental outcomes - rather, individuals behave selectively and actively with respect to the people, places and events that engage and challenge them."