Noting that the males with burdensome traits are almost entirely those in polygamous species, where a minority of males generally mate with many females, Darwin had an insight. He realized that if females found these male burdens more "attractive," and if that attractiveness resulted in more matings by burdened males, then the increase in matings of a few sons might offset the death of many other sons as a result of the burden. In effect, if the success of the surviving males produced enough offspring to cover more than the loss of potential offspring from their lost brothers, then the female who mated with a burdened male had chosen correctly.