Transman who birthed baby wants to be legal father

[NotNachoing]

https://www.pinknews.co.uk/2018/10/01/transgender-baby-first-no-legal-mother-landmark-case/?utmsource=Facebook&utmmmedium=Buffer&utmcampaign=PN

So because this man, who identified as a man in conception and when pregnant and after birth, decides biology is nothing (until he wants to use his biological female parts - or is it his man-uterus now?) his child is going to be gaslighted for life.

Oh, and he wants the law changed so a child can have no biological mother documented on the child's papers.

I’m confused. Why are they using terms like “make believe gender roles” and “birth not being...feminine” as part of their argument? It’s biology, it’s not a”gender role”? It’s about sperm and egg. And I don’t understand the privacy argument. Surely now they’ve transitioned then previous names on the birth certificate aren’t relevant? Or have I missed the point?