The nature of covariation between autistic traits and clumsiness: a twin study in a general population sample.

The team studied 398 twin pairs from the general population.

Parents filled out two short checklists: one on clumsy motor slips and one on autistic-like behaviors.

Using twin statistics, the researchers asked how much of the overlap is genetic.

Clumsiness and autistic traits shared about two-thirds of their genetic influences.

The link was almost entirely genetic, not because one trait causes the other.

Ho et al. (2005) first noticed twin boys score slightly higher on autistic traits than single-born boys.

The new result explains why: the same genes that raise clumsiness can raise sub-threshold autistic traits.

Isaksson et al. (2019) used the same twin trick on mind-reading skills.

They showed the autism–social-cognition link vanishes within pairs, just as clumsiness here is tied to shared genes, not direct causation.

Zubizarreta et al. (2025) later kept the co-twin design but swapped clumsiness for camouflaging stress.

Their mixed findings prove the twin method keeps revealing when family genetics, not the trait itself, drives later outcomes.

If a child shows both clumsy motor moves and borderline autistic behaviors, think shared biology instead of one problem causing the other.

When you see a motor-red flag during assessment, probe social-communication skills too; the same family genes may load on both areas.