But Transparentis far from a one-woman show. Maura's three children are, in their different ways, damaged and difficult. Prim, sexually conflicted Sarah (Amy Landecker) dumps her dull, suburban husband for college flame Tammy. Ali (Gaby Hoffmann) is flaky, directionless and lovelorn, forever leaching off her parents. Record exec Josh (Jay Duplass) is frantically promiscuous and has an unhealthy relationship with his former nanny. None of them reacts to Maura's news with unvarnished positivity; all of them focus on how it affects them.
Their responses - running from calm acceptance to complete incredulity - reflect the feelings of both Soloway and her sister, Faith, who's also a writer on the series. It must have been painful, mining their experiences for the screen, I suggest.
"Painful and joyful," the 50-year-old Soloway corrects me. "We're getting to know this new person as she wants to be known, and transitioning into a family where our story is internationally known. But it's hard when someone in your life goes, 'Is that how you see me? That's not how it was'."
Transgender was, according to Collins Dictionaries, the word that experienced the second greatest rise in usage in 2014. This startling storming of the mainstream is mostly thanks to the increasing confidence and activism of the trans community, but also in part to series such as Transparent, Netflix's Orange Is the New Black and BBC Two's Boy Meets Girl (all of which feature transgender actors in major roles).
And then there's Caitlyn Jenner. The former Olympic decathlete announced her intention to transition in a widely publicised interview with American journalist Diane Sawyer, before appearing on the cover of Vanity Fair in July.
"I know she watched the show," says Soloway. "I know her kids did. I expected a 50/50 reaction to the Diane Sawyer interview on social media, but it was 100 per cent positive. Transparent has this question at its centre: 'Will you still love me if... ?' To see that the response to Caitlyn was a big yes was just amazing. So on Transparent, we're just riding a wave."
Tambor's nuanced, thoughtful performance as Maura/Mort has been one of the revelations of the show. Was he surprised to be cast? "No, and I guess I should have been!" he says. "I looked at that script and thought, 'There's my Lear.' I didn't think of the ramifications. Now, I go to work thinking of the honour and responsibility of playing this role. I don't take that lightly. For all the good stories, you still hear the horrifying ones, so it can't be overstated: lives are at stake."
Looking back, Soloway says she might have approached the casting of Maura differently.
"It never occurred to me to find someone trans to play the role," she says, "but shortly after we made the pilot, I started understanding the politics of it. I have a few defences - Jeffrey Tambor is an amazing actor, and because the world knew him as a cis male, they got to watch someone they knew and loved transition."
She pauses. "Are you aware of the word 'cis'?"
As it happens, I am: "cis" means someone whose gender identity aligns with their gender at birth. Trans issues present something of a lexicographical minefield, one that Tambor is delighted to assist in navigating.
"I met someone the other day who kept talking about 'Bruce, Bruce, he, he', and I kept saying, 'Caitlyn, Caitlyn, she, she'," he says. "But I was ignorant with a capital 'ig' before I got the part. I still have a lot to learn, but Maura is also very new to the movement, so we're on the same page. I've never felt like I've 'got' Maura, because Maura hasn't 'got' Maura yet, either. She's like a teenager; she doesn't quite know how to put on make-up yet."
While the flighty, selfish young Pfeffermans had a near-monopoly on bad behaviour in the first series, the second reveals more about the extent to which Maura's behaviour is responsible for her children's dysfunction.
Soloway, who is married with two children, has become a vocal advocate and practitioner of "transfirmative action". Transparent involved trans consultants from the start, but Soloway has now populated cast, crew and writers' room with trans people and insisted on gender-neutral bathrooms. And she's brought what she calls a "feminine energy" to filming: she prefers not to shout "action!" lest it sound too close to "attack!", while on a Soloway set, "if you can't cry, you're a liability".
And only one episode of Transparent's second series is directed by a cis male.
"So few women directors are getting hired," she says. "So few women run shows. White cis men aren't actively attempting to stop other people from telling the stories, but storytelling is so much fun - why would anyone give up this power? No wonder they're not saying, 'Let's hand the camera to women, to people of colour, to queer people, to trans people'."
After the seismic impact of Transparent, who would bet against her? "We have so far to go," she says, "but things seem to be finally changing. We've just got to grab it."
TV profile
Who: Jill Soloway, creator of Transparent
What: Season 2
Where and when: Available on Lightbox now.
