Lordosis is a reflex action that causes many non-primate female mammals to adopt a body position that is often crucial to reproductive behavior.
But when environmental conditions are favorable and the female is in estrus, the estrogen hormone, estradiol, induces sexual receptivity by the neurons in the ventromedial nucleus,[7] the periaqueductal gray, and other areas of the brain.
These convey an impulse to neurons in the medullary reticular formation which project down the reticulospinal tract and synapse with the neurobiological circuits of the lordosis reflex in the spinal cord (L1–L6).
Consequently, these reductions in exposure to gonadal hormones around puberty can result in decreases in sexual behavior in adulthood, including displays of lordosis.
[11] In a 2017 study, using 3D models and eye-tracking technology it is shown that the slight thrusting out of a woman's hips influences how attractive others perceive her to be and captures the gaze of both men and women.
[12] The authors argue "while reflexive lordosis posture is not exhibited by human females and receptivity is not passive or obligatory for them, a manifestation of lumbar curvature might serve as a vestigial remnant of proceptivity-/receptivity-communicative signal between men and women".
[13] Previously, anthropologist Helen Fisher also speculated that when a human female wears high-heeled footwear the buttocks thrusts out and the back arches into a pose that simulates lordosis behavior, which is why high heels are considered "sexy".