Yes, it is okay for men to wear tortoise-shell sunglasses. In fact, If tortoise-shell sunglasses fit for you not depend on you are men or women. It is up to what type of person you are. If you are a man like johnny depp, tortoise-shell sunglasses must work well on you. Anyway, you shall try on and see how you look with the sunglasses. If the sunglasses make you look well, take it. Or just quit it for other suitable one.