"She always looks at bones, not just the pelvic, and goes 'male' or 'female'"
These would be educated guesses. Even if you're an expert and can examine the entire skeleton all you have at best is an educated guess.
from above linked article:
"ATSU assistant professor and biological anthropologist Caroline VanSickle told AFP that professionals often cannot say with any certainty if an individual was male, female or other just by looking at their bones.
“We can offer a fairly educated guess, but even then we sometimes get the answer wrong or end up with inconclusive results,” VanSickle says.
She added there is currently “limited data” on how hormone replacement therapy (HRT) affects bone structure, which makes it even more tricky to define the facts about a centuries-old skeleton.
“We also lack methods to identify intersex individuals, who make up around two per cent of the population,” she added."