Handlebars are one of the most overlooked and underrated components on the bike. They help define your posture, support your hands, and determine the ease of reaching your braking and shifting controls, yet often they only allow for comfort in any given hand position at the expense of another position. The hand comfort and postural comfort can be ensured in all positions with just a little time finding the handlebar that best matches the rider.
Many riders (and even bike shops) neglect to appreciate the variability of handlebars and how customized a bike can feel based on the variations. Often widths are compared, but not the relative angle of the drops, or how the top of the bar leads into and intersects with the brake/shifter hood, or the reach and depth.
The reach is especially critical. In bikefitting terms, a handlebar with a 90mm reach compared to another of only 70mm has the same effect in arm extension and torso posture as the difference between a 56cm frame and a 54mm frame. Very few cyclists don't care what frame size they buy, but most don't know the reach of their handlebars, or even that the reach is worth their consideration.
From Left to Right:
Ritchey Logic II - 78mm
PRO Vibe 7S - 79mm
3T Rotunda - 83mm
Profile Design Legra SS - 70mm
FSA K-Wing Carbon - 80mm
In terms of shape, the ideal handlebar simultaneously gives you a comfortable platform on top of the bar which allows for a tangential extension of the hoods before the curve into the drops - so that the rider's hands don't have to span (or fall into) a trough - while allowing for an angle in the drops that the rider can hold with a relaxed neutral wrist angle. Finding the correct angle is easily found through trial-and-error, not unlike getting an eye exam.
Finally, "women specific" bars are often shorter and shallower, but there are so many bar styles on the market that have more "compact" dimensions that gender specificity is not really an issue. Knowing what dimensions and angles you need, however, is.