Twin studies.

A scientific study that either uses twins for some purpose (to detect differences in lifestyle choices) or seeks to replicate the results of an existing study.

A scientific study that either uses twins for some purpose (to detect differences in lifestyle choices) or seeks to replicate the results of an existing study.

twin cities

Yes, it is possible. In one study, the chance that an identical twin has autism when the other does is 82%. That means that 18% of the identical twins did not have autism. It is much more likely that an identical twin will have autism if the other does than that a fraternal twin or other sibling will, but it does not happen every time.