This story is, on the service, somewhat funny (not haha funny).
This biologically female baby, AFAB, who could very well be cisgender as in she will be raised a girl, is biologically female and will identify as/with such is legally male.
But the actual issue here is that yes, they were told it was unlawful to try and change her birth certificate or register for another. The law prevents this from happening and the only other way to do it is to be transgender and jump through a million fiery hoops for the possibility of being allowed (and law on the matter is subject to change).
As they pointed out, right now she’s not trans (they were fine with the idea of her one day being so) but those who see her birth certificate (schools, work) might make that assumption and might be transmisogynistic about it.
This AFAB, biologically female child is TMA based on this alone, but also what if she herself doesn’t believe she was born female because of it - that’s a worry her parents had because of it - whether it’s a valid worry or not.
The lesson here is first fire the registrar who made this issue (it’s the second time they have, but previously amendments were allowed) and second of it make it easier and legal to make changes and amendments to birth certificates.