A good deal of common sense is useful when selecting a harness - mens harnesses come in infinite variations but there are also smaller harnesses for children and harnesses specifically shaped for women.
Manufacturers sizing guidelines are a starting point for selecting a harness that is safe to climb in but a comfortable fit may go beyond that. The more basic harnesses are usually the most cost effective and a safe alternative by being generic rather than specialised, however some harnesses are featured to be more adjustable. For example, a floating waistbelt or dual closures can help to keep padding central when at the extremes of adjustment or when worn over winter layers. Some harnesses have an adjustable rise and can be considered unisex although a true womens specific harness tends to have a longer rise (the dimension between the waist and leg loops) and also a more conical shape to the waistbelt which is generally worn slightly above the hips rather than across.
If you're at all unsure on the sizing of a harness or the suitability of a design then feel free to email or call for advice.