In one of his most influential books, Charles Darwin made an observation about women.

As far as he could tell, women appeared to be sadly lacking compared with men in every sphere of life:

“The chief distinction in the intellectual powers of the two sexes is [shown] by man attaining to a higher eminence, in whatever he takes up, than woman can attain,” he wrote in the Descent of Man published in 1871.

What could possibly explain this distinction?