One of the questions I am frequently asked is “I know women wear the flower leis; what kind of lei do men wear?”
See this topic on Quora: Hawaiian Lei
The answer is that men, women, māhū, boys, girls, and any anyone else can pretty much wear whatever lei they wish. The important thing is that the lei be given and worn with aloha.
When I select a lei for someone, the first thing I consider is what the person will be doing, and how the person will be attired, when wearing it. Knee-length strands of pīkake would not be a good choice for someone who will be riding a horse, or surfing. But it might be perfect for a stately formal event, or for hula.
The next thing I consider is allergies. Be sure the recipient is not allergic to the materials used in the lei!
After that, I think of favorite flowers, colors, or anything else I know about the recipient.
There are some additional customs: Only give open lei to someone who is hāpai (pregnant). Since Victorian times, fragrant white lei are popular for brides. Lei hala are favored for graduations, funerals, and people from Puna. Strongly scented lei are avoided as gifts for musicians until after the performance.
Some flowers and foliage will stain clothing, but can worn with a low-cut or off-the-shoulder garment. Those wearing clothing which would be damaged might accept the lei with their hands, and place it where they can enjoy seeing it.
So feel free to give maile to a woman, and roses to a man. The lei is a cherished gift, and should be accepted as such.