I have often come across the term "women's motorcycle helmet". Is there such a thing? Do manufacturers categorize helmets that way? The simple answer is no, not really. Technically, every helmet is a woman's motorcycle helmet. The same goes for motorcycles, in my opinion. Every motorcycle is a woman's motorcycle.
So what kind of helmets are best for women? How do you make that decision? Some manufacturers have tried to do that for you by creating cute, pink helmets to distract you from the reality of how to properly choose a helmet. And, they're pretty good at it. Let's face it ladies, we're attracted to cute things. Pink! Glitter! Gold! Flowers! It can be overwhelming at times. But, when it comes to protecting ourselves, it's crucial to find a helmet that's real, has proper DOT and Snell or ECE certifications to show that it's been properly tested to ensure that it's going to save your head from serious injury.
I posted awhile back with a few full face options that were a little 'softer' in design and made to appeal to women riders/consumers. A couple of these might be discontinued designs, but manufacturers are continually trying to come up with more that women might like.
http://www.gearchic.com/blog/?p=621
Another one I want to add to this list is the Arai RX-Q Oriental. It's a gorgeous helmet with a very unique design. Arai seems to be getting back to more complex designs and this one is far more beautiful in person.
Remember that although many women do have smaller heads, not ALL women do. I've had to put a few women in Large and XLarge sizes before. For the most part though, I will say that the majority of helmets I've had to fit for women are between XXS and Small (and one time, XXXS). It's all about fit and shape. Any helmet that fits the shape of your head will be your helmet! Hopefully that manufacturer will have color schemes that fit your styles and color choices too. But if not, I hope that won't keep you from buying 'the one'.
(The helmet pictured above is a Shoei X-12 Vermeulen)