Men and women have many differences and shoes are just one of them. A womans shoe isnt merely a smaller version of mans shoe. The design is different to allow for differences in the shape of the foot and weight applied to the heel.
Mens running shoes are generally stiffer than womens shoes. This allows for more support and motion control whereas womens shoes tend to be a little more flexible.
For a long time, running shoe manufacturers specialized mainly in the construction of mens running shoes and basically build scaled down versions for women.
In recent years however, many manufacturers have taken to designing running shoes specifically for women which take into consideration the differences in the build of womens feet.
Since men of the same height tend to weigh more than women, mens running shoes are designed to be tougher and have more cushioning in the sole to absorb the pounding caused by the additional weight.
The heels are typically designed to absorb shock of greater intensity. These extra features tend to make the shoe stiffer which adds additional support for the male foot, but which can make it hard for a female to move and flex...