The form of the modern human bony pelvis is a reflection of its multiple functions. Sexual dimorphism in pelvic shape is related to the unique constraint in females for one of these functions, obstetrics. Competitions between locomotion and obstetrics and visceral support and obstetrics have resulted in evolutionary trade-offs in pelvic morphology. This research examines the effect of specific variables related to these trade-offs on modern human pelvic morphological variation:​ sex, population, and the presence of a pelvic floor disorder (PFD).

These studies utilize geometric morphometric analyses to statistically compare pelvic shape within and between groups. Pelvic landmark data were collected for five matched samples, each of which was selected to model one of the variables under consideration. Pelvic shape in each sample was quantified using a combination of morphometric techniques, including Generalized Procrustes Analysis and Euclidean Distance Matrix Analysis.

The first study tested the relative effects of sex and body mass on pelvic shape. There was a greater proportion of variance attributed to sex in distances approximating the posterior space;​ in contrast, there was a greater proportion of variance attributed to body mass in distances approximating the anterior space. Results from the second study demonstrated that although population has a significant effect on patterns of sexual dimorphism, the majority of obstetrically critical dimensions demonstrate overwhelmingly similar patterns of sexual dimorphism. Finally, results from the third study demonstrated that women with PFDs display medio-lateral widening of the pelvic midplane and outlet, when compared with their unaffected counterparts.

Perhaps the most interesting result from the study was the finding that populations with different body proportions exhibit similar patterns of sexual dimorphism in pelvic shape, particularly in obstetrical dimensions. These data demonstrate that, although body shape affects overall pelvic shape, it does not directly influence patterns of sexual dimorphism. Several explanations, including female buffering, correlated responses, and nutritionally-affected pelvic growth are offered as potential explanations. These results provide interesting insight about interand intra-populational variation in pelvic shape and are relevant to studies of human evolution, adaptation, and modern obstetrics.