Genetic studies suggest postmenopausal women are so important in terms of ensuring the survival of grandchildren that we evolved genes to keep their brains healthy.
Genetic studies suggest postmenopausal women are so important in terms of ensuring the survival of grandchildren that we evolved genes to keep their brains healthy.
Plus, a few percent chance of no reproduction isn’t exactly a huge penalty, depending on what benefits a trait may bring. The relative narrowness of the human birth canal is another example. Enough average width to avoid lethal outcomes to inevitable natural variation would result in pretty big gait issues.