I think this kind of missed the point - It is a question of taste - there is no absolute answer. Clearly this type of buckle has origins in female strap designs, but Apple will never state formally that it was designed for women. My opinion is that the buckle, combined with the black strap, is sufficiently modern in design that it could easily be worn by a man, but then again I've not seen one in person yet.
I bet more people will agree it's a feminine band once they see it in person. There were a significant number of responders who weren't sure and needed to see it in person. The stock photos don't do justice in illustrating how large the clasp is (like the real life photos I posted earlier).