In fact, the osteological evidence had been raising questions about the male assumption for decades before the DNA study. Vilkans’s 1970s assessment was not tentative because osteological methods were inadequate. The methods she applied were capable of identifying female morphological markers. The problem was not the analysis; the problem was that the analysis’s conclusions did not displace a deeply entrenched interpretive tradition.
Modern osteological sex determination rests on analysis of multiple skeletal elements that show sexual dimorphism — differences in shape or proportion that correlate with biological sex. The pelvis is the most reliable indicator: female pelvises typically show a wider sub-pubic angle, a more circular pelvic inlet, and other morphological features related to childbirth. The skull also shows dimorphic features: males typically have more prominent brow ridges, a more angular jaw, and a more pronounced occipital protuberance. Long bones can provide additional evidence through measurements of joint size and shaft diameter.
The problem with the Bj 581 remains is incompleteness. The skull was missing or fragmentary — precisely the element that would provide the clearest sex determination. The available elements — the forearm bones, the pelvis — were consistent with female morphology but could not individually carry the full weight of a confident sex determination. Vilkans’s assessment was hedged because she was working with incomplete evidence.
Kjellström’s 2016 assessment, coming after decades of further development in the field and with access to a larger comparative database, was more confident but still limited by the same incompleteness. She assessed the morphology as female. The museum records and the field’s interpretive tradition said male. The DNA was the tiebreaker.