Vaginal size
According to Wikipedia's summary, a number of research studies have been made of the dimensions of the human vagina.
A 1996 study by Pendergrass et al., using vinyl polysiloxane castings taken from the vaginas of 39 Caucasian women, found the following ranges of dimensions:
- lengths (measured using rods): 6.9 to 15 cm (2.7 to 5.9 in);
- widths: 4.8 to 6.3 cm (1.9 to 2.5 in);
- introital diameters: 2.4 to 6.5 cm (0.94 to 2.56 in)
Research published in 2006 by Barnhart et al., gave the following mean dimensions, based on MRI scans of 28 women:
- Mean length from cervix to introitus: 6.3 cm (2.5 in).
- Mean width:
- at the proximal vagina: 3.3 cm (1.3 in);
- at the pelvic diaphragm: 2.7 cm (1.1 in);
- at the introitus: 2.6 cm (1.0 in)
Even though these limited data sets might not be statistically significant it's pretty obvious that doll vaginas do not exactly mimic the female anatomy.