How do archaeologists determine the gender of a skeleton?

When archaeologists come across ancient human skeletons, one of the first things they try to do is figure out the gender of the skeleton, whether it was male or female. While it might sound straightforward, the process is neither simple nor it’s always accurate."Overall, we're looking at shape and size differences between the sexes," said Sean Tallman, abiological anthropologist at Boston University, in an interview with Live Science. However, he added, "no one method is 100% accurate."One common way to estimate sex is by measuring long bones, like the femur and tibia. These bones are generally larger in males. “On average, males are about 15% larger than females,” said Kaleigh Best, a biological anthropologist at Western Carolina University, in an interview with Live Science. But factors like diet, health, and genetics can all affect bone size, which makes this method only about 80% to 90% accurate.This technique looks at specific features of the pubic bone. A taller and narrower pubic bone often means that it belongs to a male, while a wider one usually indicates a female. With this method, it is assumed that a trained expert can predict the sex of a skeleton with about 95% accuracy.By analyzing ancient DNA, scientists can often figure out the chromosomal sex with up to 99% accuracy. The process involves identifying genes linked to sex chromosomes. However, it is hardly unlikely that DNA would survive over long periods, especially in harsh conditions. So it might not always be an option.Even with these advanced techniques, some skeletons defy simple classification. "Sex is not binary, but it may be bimodal," said Donovan Adams, a biological anthropologist at the University of Central Florida. This means there are two main patterns — male and female — but also a significant number of people who fall somewhere in between.Experts say that about 1.7% of people are born intersex — a term for individuals with a mix of male and female biological traits. That’s about 1 in 50 people. Intersex conditions can include things like XXY chromosomes (Klinefelter syndrome) or conditions like CAH (congenital adrenal hyperplasia), which can make female genitalia appear male at birth.Virginia Estabrook, a biological anthropologist at the University of Maryland, Baltimore County, explained to Live Science how she studied the skeleton of Revolutionary War hero Casimir Pulaski, whose bones appeared female, even though records show he lived as a man. One explanation could be CAH.Understanding identity from bones alone is tricky. Bones can reflect lifestyle habits that may be linked to gender roles, like archery or grinding grain, but that doesn’t always line up with biological sex or personal identity. While with new tech, determining the gender of a skeleton has become more accurate, we still have a long way to go.