The Victorian Government has introduced a Bill, the Births Deaths and Marriages Registration Amendment Bill 2016, to amend its law on birth certificates to allow changing the gender on the certificate to be made easier. (The Bill was approved by the Lower House on 15 Sept 2016 and is awaiting consideration by the Legislative Council.) There are many problems with the policy represented by this legislation (see a good summary from Murray Campbell, “Victorian Government and Birth Certificates” Oct 26, 2016)). But what I want to focus on here is the interaction of the new law with the law on marriage. In my view the law will create a host of legal uncertainties at best, and is quite likely to be unable to achieve its apparent aim of allowing Victorians born in one sex to live for all purposes as if they were of the other sex.