My advice would be to test ride as many bikes as possible. I am 5'9". I started with a men's 58 KHS entry level bike that fit really well. I rode it comfortably for about 6 years before upgrading to a Trek Domane WSD 4.5 with a 54cm frame that fits perfectly. I think I test rode at least 20 bikes before selecting the Domane. What I learned was every manufacturers geometry is a bit different and you really can't go by size or men's vs women's. You need to experiment and see what is most comfortable.