He doesn’t normally talk about the delivery itself. “But I gave birth in the water and it was amazing,” he says, eyes flickering up in almost ecstatic recall. “Nothing will ever beat that.” Dysphoria melded with euphoria. “For me,” he says, “it was the pinnacle of human experience.”

As McConnell lay in the hospital with the baby in his arms, the new parent realised how important it was to savour everything. “To honour the fact that I have this incredible bond with my child because I gave birth to [them],” he says. “I’m not like other dads, but that doesn’t mean I’m any less of a dad.”

He frowns after saying this, in case it could offend mothers. “This is not about erasing the fact that it’s usually women who go through this,” he says, “I don’t ever want to be seen to be coopting this experience away from women. It’s just that someone like me can also go through this and it can be wonderful.”

The first two weeks, he says, were blissful — carrying the baby in a sling, strapped to him constantly.

But then he had to register the birth.

There was a small chance, he thought, that the online system might let him register as the father, so he put his name in the father box on the form, and marked “XX” under mother. (In Britain, the mother space cannot be left empty, but the father one can be.)

Soon after, McConnell received a phone call from the register office. An email followed, clarifying: He would have to register as the mother.

He phoned Andrew Spearman, his solicitor. Spearman confirmed McConnell’s fears: The only way around this was to take the Registrar General to court.

The legal process began. The baby was only 2 weeks old. “I had to muster strength I didn’t really have,” he says. Having his and his child’s anonymity protected by the court helped, however. He would be referred to only as TT and his baby as YY.

McConnell did not know then that anonymity wouldn’t last — even though it was almost inevitable. He had begun filming a documentary about his personal experience of becoming a father, called Seahorse. It would not mention the legal case and, he expected, wouldn’t be released until long after the case concluded. “I thought I could keep them separate,” he says. The calculation would prove flawed.

But before he had to face that, there were two preliminary proceedings for the birth certificate lawsuit in 2018, which led to a full hearing at the High Court in February this year. The legal arguments fanned out from four sources: McConnell’s legal team, the government’s legal team, representatives of McConnell’s baby, and independent experts.

The arguments were, initially, straightforward. McConnell’s team said that because the British government had already officially recognised him as male with a gender recognition certificate before he conceived, and because the law states that this is “for all purposes”, then it must cover parenting. A recognised trans man who has a child is therefore the father. To deny that would be to discriminate on the grounds of gender and pregnancy.

They argued that forcing McConnell to register as the “mother” would out them both, as a child with a trans parent, forever revealing this to any authority that requested the certificate.

The baby’s legal team agreed: that the current situation is a breach of the baby’s right to a private and family life. “The government has produced no evidence that registering the Claimant as YY’s father would not be in YY’s best interests,” papers submitted to the court concluded.

The independent experts added that making McConnell register as mother would constitute “profound incongruence with the child’s familial reality” which “has the potential to have a harmful impact on the children of transgender parents”.

But the government— lawyers for the Registrar General — replied that the current system simply does not allow McConnell to be declared the father or parent because in law “father” means the sperm provider or the male partner of the mother. And “parent”, meanwhile, can only be used for the female partner of a woman who gives birth.

The arguments then became messy. Because McConnell conceived through artificial insemination, a row ensued over the Human Fertilisation and Embryology Act 2008 because of how it defines mothers who receive such treatment. McConnell didn’t fit the description, as he used his own eggs, but for the government that mattered not: He gave birth.

From here, the case began to fling open doors in family and human rights law, exposing behind each one a series of jolts.

Jolt one: Many would assume that the government was defending the traditional idea of what a mother and father are — but it was McConnell’s team who argued that a “mother” is female, that it is a gender-bound legal term just as “father” is. (Furthermore, they reasoned, a trans man whose wife gives birth is registered as the “father”, so why not if they themselves give birth?) Yet the government stated the opposite. “A man can be, and in this case is, a mother,” argued Ben Jaffey QC.

The second jolt was what a birth certificate really is. It is commonly considered a record of biology or genetics. But the case exposed the extent to which this is no longer true: that since the 1990s, when surrogacy and same-sex adoption became more routine, the certificate has become a legal record.

Through this, McConnell’s position looks less unorthodox, his team argued. Not only are there babies in other countries registered with a father and no mother (two recent cases in Sweden, for example), there will also be children in the UK already in this situation — who were born to a surrogate in a country such as the US where the mother need not be named on the birth certificate.

The third jolt was the extent to which nowhere in the law had anyone considered that a transgender man might become pregnant. Twelve years after the first known case of a man giving birth after transitioning, there was still no legal provision — a no (trans) man’s land.

But finally, the government’s lawyer fought on a different front altogether: the hypothetical. What if the child grows up and disagrees that McConnell is their father? Would they be able to change the birth certificate? And what if McConnell had a partner who disagreed that McConnell should be registered as the father?

In his lawyer’s office after the hearing, McConnell scorns this argument. “It’s a bit like saying, ‘What if two gay parents’ child grows up and is homophobic and doesn’t think gay people exist?’ They’re still your parents and they’re still gay.”

Even so, the emotional resonance encircling this case will be impossible for many to ignore: mother, motherless. Previously, our depictions of the latter, aside from orphans, are in Greek mythology: the primordial deities born from Chaos — the abyss. To be motherless is to be from the void. Loveless.

Except that, says McConnell, many babies already do not have a mother, even though all were delivered: children raised by two fathers or one father, or whose mother is a surrogate or is dead. Children who are abandoned.

“That idea of sacred motherhood is quite sexist,” says McConnell. “Where does that leave women who don’t want children? What does that say about gay fathers? And men who raise children?”

Instead, he says, objections to a birth certificate with no named mother are a smoke screen for something darker, “a front for a more visceral, slightly ickier reaction people are having when they see any man raising a child single-handedly or in a gay relationship.”

McConnell doesn’t mind whether he is allowed to register as the father or the parent on the birth certificate: For him, either is right. “Ultimately, we’re all parents, and that’s what matters. There needs to be a solution for everyone.”

But he is aware how tectonic some of this feels to some. “I’m sure this seems like a huge, bizarre change,” he says, “but maybe 50 years ago people would have said the same thing about equal marriage.”

It is also standard for those at the vanguard to be confronted. While McConnell thought he could protect himself and his child by making the film while anonymously suing the government, the newspaper groups were, as a result, able to mount a strong challenge: that the public might well assume it was the same person in the documentary and in the court case, so why shouldn’t they link it?

In July, the day after the papers (including the Daily Telegraph, the Sun, Daily Mail, and Daily Mirror) won, the Telegraph splashed his picture on the front page and commissioned a writer to accuse him of “misogyny” for imposing “motherlessness” on a child, implying that it was all for McConnell’s selfish desires. The writer had not spoken to him.

That night, a screening for Seahorse, his documentary, was held in Soho. It provides, in its domestic intimacy, a further surprise: how relatable his extraordinary life is. At a dinner party, the camera closes in further and further on his face, eyes sinking, collapsing, a thousand miles from the chatter. The alienation pierces. Enough to make you flinch.

Afterwards, Esme, his mother, approaches BuzzFeed News. She talks about hers and McConnell’s lifelong feminism, and how horrified she is by those who wish to exclude and demonise trans people like her child. She has a great line in the film: “Everyone should experience pregnancy. Especially men.”

Two months later, the judgment comes through, and as we sit again in his lawyer’s office, the ramifications of him losing begin to hit.

First: The Gender Recognition Act, as clarified by this judge, now only recognises a trans person’s gender if they do not have children. If they do and register as the parent in their acquired gender, they will be doing so unlawfully, even if they have a Gender Recognition Certificate. In other words, a trans man whose wife gives birth cannot be listed as father. Similarly, a trans woman will have to be listed as father.

“The identities of trans people get invalidated as soon as they become parents,” says McConnell. This is a “farce,” he says, and “de facto sterilisation”. British transgender people would have to knowingly forego their gender identity if they want children.