Changing 'sex' on a birth certificate (and it is sex, not ‘gender’) makes that information useless for medical research and demographic purposes.

It falsifies the information on the certificate.

The NSW Registry of Births Deaths and Marriages notes that the information on birth certificates is used ‘for statistical, medical research, community planning purposes, law enforcement and other uses provided for by law’ ( But changing sex on birth certificates at will, as the proposed Victorian bill allows, would invalidate any of these uses concerned with sex ratios in the general population.

To date, the transgender people who have changed the sex recorded on their birth certificates are few in number. Those wanting to have their new ‘sex’ recorded on their birth certificate must ‘have undergone a sex affirmation procedure’ (i.e. castration for men) and those few numbers are not likely to make much difference to the sex ratio of the population. However, the numbers are likely to grow across Australia given that Tasmania has already passed legislation that removes that requirement and Victoria is poised to follow suit.

Whatever their numbers though, the fact that some birth certificates can be changed means that none can be trusted as records of (biological) sex. There is no way of telling whether the sex marked ‘female’ on a birth certificate is the sex of someone born female, or whether it refers to someone born male—unless there is some marker that indicates the change.

Whether or not policy makers care about the consequences of these changes for women, they should have concern for the impact on medical research and the impending degradation of demographic statistics and historical research.

For example, a recent medical research study showed that the death rate after blood transfusion was highest if a donor had ever been pregnant:

Pregnancy might affect a woman's immune system in some way that makes her blood more risky for a man, van Hasselt said.

However, the risk is unlikely to prompt any immediate change in blood donation policies, said Dr. Louis Katz, chief medical officer for America's Blood Centers.

"I think there's enough of a signal that it needs be studied, but I certainly wouldn't change anything right now," Katz said. "It needs to be followed up."

The American Red Cross agreed. The study "needs confirmation as conflicting studies also exist," said Dr. Mary O'Neill, its interim chief medical officer.

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