'Memories' pass between generations

The findings provide evidence of "transgenerational epigenetic inheritance” - that the environment can affect an individual’s genetics, which can in turn be passed on.

One of the researchers Dr Brian Dias told the BBC: “This might be one mechanism that descendants show imprints of their ancestor.

"There is absolutely no doubt that what happens to the sperm and egg will affect subsequent generations.”

Prof Marcus Pembrey, from University College London, said the findings were “highly relevant to phobias, anxiety and post-traumatic stress disorders” and provided “compelling evidence” that a form of memory could be passed between generations.

He commented: “It is high time public health researchers took human transgenerational responses seriously.

"I suspect we will not understand the rise in neuropsychiatric disorders or obesity, diabetes and metabolic disruptions generally without taking a multigenerational approach.”

In the smell-aversion study, is it thought that either some of the odour ends up in the bloodstream which affected sperm production or that a signal from the brain was sent to the sperm to alter DNA.“