8 Dec But if you're looking to update your info a bit from the '60s, fast-forward 30 years later to a study in Gynecologic and Obstetric Investigation, where researches took vinyl polysiloxane casts of the vaginas of 39 Caucasian women ( some had experienced childbirth, some had not), and discovered an. The dimensions and shape of the human vagina are of great importance in medicine and surgery; there appears to be no one way, however, to characterize the vagina's size and shape. In addition to variations in size and shape from individual to individual, a single woman's vagina can vary substantially in size and shape. PubMed journal article Comparison of vaginal shapes in Afro-American, caucasian and hispanic women as seen with vinyl polysiloxane castin were found in PRIME PubMed. Download Prime PubMed App to iPhone or iPad.