Crossbars are typically used on women's bikes in order to integrate a bigger range of gears into the bike, or to make it easier to get across different distances. While men can use the same gear ratios on a bike, they may not be able to use as many different gears due to their smaller hands and fingers. By adding crossbars, men can increase their chance of getting the most out of their bike by using more gears, and also increase the range of motion that their hands and fingers can use.