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Donald Trump's talking points perhaps reflect a lack of empathy, but could his genes be partly to blame?
At a meeting in February with survivors of a Florida high school mass shooting, US president Donald Trump was photographed holding a list of aides memoire which included the prompt, "I hear you".

The need to remind himself to at least appear sympathetic to the feelings of children who had witnessed their school mates being shot by a man with an assault rifle was interpreted by many - if not most - as indicating that Mr Trump was somewhat deficient in the empathy department.

And perhaps he is - but if so he might not be fully to blame.

A new study based on questionnaire responses matched to genetic samples obtained from 46,000 people suggests that genes are at least partially responsible for a person's ability to feel and express empathy.

The study, published in the journal Translational Psychiatry, was conducted by a team headed by Varun Warrier of the Autism Research Centre at Cambridge University in the UK, in conjunction with US genetics company 23andMe.

Warrier and his colleagues made use of data obtained by the popular business. Each customer completed a questionnaire designed to reflect empathy potential, based on a self-report measure developed by other University of Cambridge researchers 15 years ago. The questionnaire delivers a standardised result on a scale known as the Empathy Quotient (EQ).

Results on the EQ scale were then compared to genetic read-outs generated by sequencing DNA contained in the saliva samples.

The results demonstrated that as much as 10% of variation in EQ scores is the result of genetic differences.

"This new study demonstrates a role for genes in empathy, but we have not yet identified the specific genes that are involved," says co-lead author Thomas Bourgeron.

"Our next step is to gather larger samples to replicate these findings, and to pinpoint the precise biological pathways associated with individual differences in empathy."

The study also found two other significant outcomes. The first was that women were, on average, more empathetic than men, even though these differences were not associated with genetic variations.

The researchers say this result implies that non-genetic factors, such as socialisation, and possibly hormonal influences in the womb, may be important in determining empathy responses.

The other result found that the genetic variants associated with reduced empathy were also linked to higher risk for autism.

"Finding that even a fraction of why we differ in empathy is due to genetic factors helps us understand people such as those with autism who struggle to imagine another person's thoughts and feelings," comments co-author Simon Baron-Cohen.

"This can give rise to disability no less challenging than other kinds of disability, such as dyslexia or visual impairment. We as a society need to support those with disabilities, with novel teaching methods, work-arounds, or reasonable adjustments, to promote inclusion."