A baby could become the first person born in the UK who will not legally have a mother if a transgender man wins a historic human rights battle.
The youngster is the child of a single parent who was born a woman but now lives as a man after undergoing transition surgery.
Lawyers have told a judge that he had been biologically able to get pregnant and give birth, but had legally become a man after the child was born.
Mr Justice Francis heard how the man “realised he was trans” several years ago.
Lawyers said he had lived as a man since then and undergone surgery to “re-contour” his upper body.
The High Court judge was told that the man was granted a gender recognition certificate more than a year ago, before the baby was born.
He gave birth following intrauterine insemination treatment.
“It is an accepted fact that a female who transitions to male may in law maintain the ability to conceive and give birth to a child,” barrister Hannah Markham QC, who leads the man’s legal team, explained in a written outline.
They said the man wants to be identified as the child’s “father” or “parent” on a birth certificate. But they said a birth registrar has told the man the law requires people who give birth to children to be registered as mothers.
The man has taken legal action against the body which administers statutory provisions relating to the registration of births and deaths after complaining of discrimination. He said forcing him to register as the child’s mother breaches his human right to private and family life.
The man said such “interference” is not proportionate or necessary in the light of changes which have “evolved in society”.
A judge on Thursday heard preliminary argument from lawyers representing the man and lawyers representing the Registrar General for England and Wales at a High Court hearing in London.
Mr Justice Francis said the issue had never been raised in a court in England and Wales before. He said if the man won his fight, ministers might have to consider changing the law.
A judge is due to make a decision after a trial in September.
Mr Justice Francis heard preliminary discussion at a public hearing, but said the baby could not be identified in media reports. He said reports should not reveal the baby’s gender or age, or the man’s age, and should not give any clue where the man and the child lived.
Lawyers said other transgender men have given birth but have been registered on birth certificates as mothers.