Much of Morris's conjecture has been turned into solid research in more recent years. For example, studies have found that males are sexually attracted to females having a waist/hips ratio of 0.7. This is universal among contemporary societies including primitive societies. When shown diagrams of women having different waist/hips ratios, male members of the primitive societies chose the 0.7 ratio and specifically indicated child bearing ability being linked to it. Females universally are attracted to males having a waist/hip ratio of 0.85.
Well, that clinches it: I'm definitely neither male nor female, since I've been attracted to (and I remain attracted to) people with widely varying waist/hips ratios within both genders.
People are so set upon this idea that sexual attractions are based upon body types. It's all so silly. If sexual attraction were based upon body types, no one would ever be attracted to anyone they met online unless they had first exchanged photographs. But I've been attracted to people without having seen their photographs, sometimes without even knowing their gender. And people have been attracted to me under those conditions too. In fact, some still are attracted to me under those conditions.
Also: this is beside the point really, but I'd love to hear the researchers try to explain exactly why they consider a waist/hips ratio of 0.85 to be the ultimate optimal ratio for a man. I can't see how it should make the slightest shred of difference.