The analysis of parturition scars has been commonly used in forensic science since it was first suggested in the 1910s. The method assumes that these scars can tell investigators if skeletal remains belong to a woman who has given birth. Now, after more than a century, researchers from The Australian National University have suggested that the underlying theory behind this method of identification could be fundamentally flawed.
In the field of forensics, new methods of identifying human remains and traces are constantly being developed -- and old methods are just as often proven to be bunk. This may be the case with this new research, which has reanalysed a number of studies on so-called 'parturition' scars and found they may not have as much to do with parturition as we once thought.
Being able to tell from a person's skeletal remains whether they've given birth -- and thus definitively identifying the person's sex in the process -- is an attractive tool for forensic investigators. However if this trait was wrongly identified, it could be disastrous for the investigation, excluding candidates who otherwise might be a match. Parturition scars have also been used for archaeological research, where coming up with an inaccurate result may cause historical inaccuracies in reporting.
While it's unclear how often skeletal remains are still analysed for parturition marks today, the technique was once widely regarded. Back in 1969 a researcher named J. Lawrence Angel claimed that one could not only tell if a woman had given birth, but also would reveal exactly how many times she had done so. When presenting a number of pubic bones of women for whom the number of children borne were known, he even went so far as to say one woman must have lied about multiple childbirths -- as her level of scarring was too heavy for only having two children under his model.
Later studies in the 70s narrowed down the types of scarring and pitting that should be used to identify a woman who had given birth, but still maintained that certain types were decently reliable indicators of childbirth.
PhD candidate Clare McFadden conducted a meta-analysis of past research into parturition scars, and found that the commonly held belief that they are caused by childbirth just doesn't hold water. In fact, the same kind of scarring on the pelvic bone can even be found on male remains -- a fact that older studies missed by only studying females.
"We found childbirth has a very weak association with these markers, but they strongly correlate with sex," McFadden said. While this scarring is much more common in females -- both those who have given birth and those who haven't -- it still appears in some men, so McFadden wanted to investigate what exactly these marks came from.
"We think they might have something to do with going through puberty, a bit like stretch marks on the pelvis," she said. "Proportionality more females than males go through significant growth of the pelvis during puberty."