In the cases of transgender and gender non-conforming people, the biological sex often has little correlation with their social identity which tends to delay the identification process. At times, transgenders prefer to alter their physical appearance in order to reflect their gender in a better way. The surgical modification for trans-women, that ends in transitioning individuals from male-to female is known as facial feminization surgery (FFS).
It involves the reduction and contour of the forehead, chin and jaw contour, and rhinoplasty, to give trans-women smoother, smaller facial features. The goal is to develop guidelines for correctly recognizing and supporting the identification of transwomen.
The post-operative FFS patients may appear morphologically female with respect to facial traits, yet results from metric methods such as discriminant function formulae used by FORDISC, will likely indicate “male” with low to moderate probabilities. The canonical variant plots often reveal an intermediary position between male and female.
FFS may result in artificially inflated bigonial breadth and mandibular length measurements. The pelvis and postcranial skeleton will likely appear and measure as biologically male. Such contradictory results should signal a closer examination of the skeleton.
This is not to say that individuals who have not undergone FFS could never have similarly contradictory results, rather the point is to dig deeper to try to understand the source of the discrepancy, as it could be highly relevant to identification.
Despite the removal of a significant amount of bone in FFS, the proportions and overall size of the rest of the skull are simply outside the range of most females. The modifications made to the skeleton and the soft tissue during FFS are intended to mimic female morphology, not female size. In addition, some of the modifications are confounded by surgical plates, pins or screws.
The morphological analysis of a MTF skull that has undergone FFS should show evidence of surgical modifications, such as screws and pins. The screws, plates, pins would be removed from the body after the treatment of injury. In case of FFS, these screws, pins and plates would remain in the bone.
There were some difficulties encountered when taking the post-operative measurements on the CTs in FFS affected areas, such as the chin. For instance, maximum chin height (GNI), was inconsistently measured as the landmark, gnathion, is generally obscured on an FFS modified chin. Similarly, the mandibular length and mandibular height, or height at the mental foramen (HMF), were challenging to take due to the addition of plates and screws.
It makes it nearly impossible to get an accurate and consistent measurement of the height at the mental foramen. In some cases, the addition of the plates added bulk to the area, and actually increased the size of the measurement. For example, mandibular length (MLN) and height at the mental foramen (HMF) were sometimes indicated as possibly artificially inflated in FORDISC.
Since measurements that yielded inconsistent results and failed the intra-observer test were excluded from further analyses, the elimination of some of the key FFS affected measurements may have impacted the final sex assessment results. In addition, almost all of the CT models were lacking the superior and posterior portions of the skull, eliminating the possibility of taking the maximum length (GOL) of the cranium.
Given that the FFS forehead contour greatly reduces the glabellar region and supraorbital projection, the GOL measurement would definitely be affected and has a strong potential to influence a sex assessment.
The results of this study demonstrate that evidence of gender can be found in the facial skeletons of MTF transgender individuals who have undergone facial feminization surgery, and that forensic anthropologists should consider individuals who do not fit into the traditional sex binary when assessing the sex of unidentified skeletal remains.