E-cigs are not necessarily designed for men or women in most cases. However, there are qualities that are prefered by different genders. The difference in clothing between men and women are important things to consider as well. Do you have big pockets to carry a bigger e-cig? A big purse? These differences can deter one sex or the other from using a particular device.
Choosing one gender or another will not show devices that are specific to that gender, it just helps to eliminate some devices that would normally not fit that demographic.