Human sexuality

sexuality2bHumans are the only primates to experience romantic love and to bond for life, the only ones to have breasts, rounded buttocks, multiple orgasms, pendulous penises and pubic hair. We’re also the only primates predisposed to monogamy, sexual modesty, private copulation and to regarding incestuous relations as taboo. How these unique features of human sexuality came about have until now, been a perplexing mystery for anthropologists. NP theory changes all that. It explains the evolutionary origins of our most unusual sexual traits, including:

cleavage-bwhy humans females are the only species of primate to have permanently protuberant breasts, even when they’re not lactating


jealousy-2What’s behind our obsession with sexual jealousy, including morbid jealousy that often results in injury or death. and private sex. Also discover why we’re the only primate to have sex in private and what’s behind sexual modesty

Almost 2000 years separates these artistic representations of isealised femininity and yet they all share one physical characteristic – a hip-to-waist ration of .7:1 Find out why this precise degree of curvature became adaptive and why it became subject to sexual selection by early human males.
Discover why, unlike every other primate, human males evolved a distinctive trapezoid shape torso —narrow at the hips and broad at the shoulders. shape—narrow at the hips and broad at the shoulders.


why beauty is adaptive. And why  having a symmetrical face, smooth skin, clear eyes and a thin nose are so important

hidden-ovulation1why are women the only female primate that doesn’t display conspicuous signs of ovulation, making it impossible for males to know when they’re fertile



why romantic love emerged in one, and only one primate species has never been explained. Learn how romantic love prevented our species from going extinct



The 15,000 year old flint plaquettes from Wilczyce, Poland (top) the curvaceous calcite Venus de Sireil from Dordogne, France (above) and the Victorian erotica suggest the modern appeal for women with curved spines accentuated by rounded buttocks (typical of the medical condition, lordosis) is not just a modern phenomena.

under-arm-hairWhy humans lost most of our body hair, except for the head, underarms and public area. No other theory explains why hair in only these areas became subject to positive selection

Them+Us explains the evolution of male sexual preferences, explaining why female breasts, bottoms and spinal curvature (lordosis) became subject to sexual selection.

See also:

Physiology     and:   Human nature