Decades ago a “women’s frame” bike had a sloped top tube so that a lady would not have to lift her leg over the top tube of a regular bicycle frame. This was originally to accommodate skirts and dresses.
More recently, many bicycle companies began offering a full range of mountain, road, hybrid and other bike types that truly are designed specifically for women. The frame geometries take into account the things that are different about a women’s body, such as height and relative arm, leg and torso length.
Many women’s bikes also feature specialized components that better fit a woman’s body, such as short-reach brake levers, drop handlebars with a shorter reach, suspension forks designed for lighter riders, and low-profile grips.