Yes, he gave birth in 2013 to their second child, in the bathroom of Lifecycle WomanCare in Bryn Mawr, with his wife, Anna, by his side.

Yes, he breastfed that child, Samson — ”a strong name because I felt I had done something strong” — for two years, serving as the family’s chief child-care provider and homemaker while Anna worked long hours as a nurse.

But Krys Malcolm Belc knew he wasn’t exactly a mom.

“When I had a baby, I thought: I don’t know anything about how to describe my gender identity. I was going to the moms’ group and the breastfeeding group … but how can you define what you are if all you know is the thing that you’re not?”

Belc, who had long considered himself genderqueer, was full of questions: What did it mean to be a mother? What did it mean to have the capacity to grow another human being? How was the experience of gestation, birth, and parenthood changing how he saw himself and how he wanted the world to view him?

“This baby helped me know the person I had to become,” Belc, 34, writes in an intimate, form-breaking, just-published book, The Natural Mother of the Child: A Memoir of Nonbinary Parenthood.

His hard-earned clarity prompted a change in every aspect of the family’s life. Five years ago, Belc began taking testosterone and using he/him pronouns. He was accepted into a writing program in Michigan and left his job in special education.

With kids in tow — by then, Anna had given birth to their third child — they rented out their Kensington rowhouse and decamped to the Upper Peninsula, where Belc began writing essays about gender and parenthood — ultimately, the memoir he wished had been on a shelf when he needed it most.

Belc had found a welcoming online community of trans-masculine people who had also given birth. But many published memoirs by trans writers had a “tonal flatness,” Belc says. Books by straight, cisgender dads tended to strike a hapless, jokey stance. Almost nothing spoke directly to his experience as a gestational parent.

Belc knows some people may bumper-sticker his memoir as the story of “‘a dude who had a baby.’ But I think of it as a book largely about motherhood. I wanted to be unsparing in my scrutiny of myself — this guy’s just looking at the good and difficult parts of his life.”

The book — its title nods to court documents for Samson’s adoption by Anna that refer to Krys as the child’s “natural mother” — consists of six essays interspersed with sonogram images, baby pictures of the author, and excerpts of documents that include Belc’s birth certificate, the midwife’s report of his labor, the couple’s marriage license, and the proof of his legal name change.

“I was trying to write a book about my experiences that was in an exciting form … a fractured book, playful in that way,” Belc says.

The memoir recounts his childhood as the oldest of six children in an Irish family that moved from Queens to Bergen County, N.J., when he was 8. Belc attended an all-girls Catholic high school and helped raise his younger siblings.

He knew he was different; as a teen, he felt miserable enough that he developed an eating disorder and stopped menstruating for more than a year. “I spent a lot of time ruminating on how profoundly bad my adult life would be,” he says.

But at Swarthmore College, Belc learned that “being trans was a thing.” He fell in love with Anna, then came out to his family as queer, but told only a few people — including Anna — that he identified as nonbinary.

She barely knew what that meant. “I learned about gay people from watching an episode of Northern Exposure,” Anna, who is 37, laughs. “When I came out to my mom, she was only afraid I would never have kids.”

The two obtained a civil union in New Jersey in 2010 — ”a real wedding,” Belc writes, “with a white dress and a seersucker suit and a cupcake tower and toasts, and a portable toilet reported widely by our guests to be quite luxurious.”

They wanted children. With the help of a sperm donor, Anna became pregnant and gave birth to Sean in July 2012, just weeks after the couple legally wed in New York.

“We wanted two babies close together. To have each other, always,” Belc writes. Anna was still breastfeeding and not ovulating, so the two opted for “the next best uterus.”

Belc writes with candor and insight about his experience of pregnancy: the physical and emotional discomfort of a vaginal ultrasound; the strained reception in a fertility clinic as he waited for his hCG numbers, while holding a squirming Sean on his lap. “I was an invader, androgynous, a trans parent in this space for women trying to conceive.”

He offers a brief history of ultrasound technology (and the absurdity of thinking a fetal sonogram can forecast a person’s gender). Another essay, called “Breasts: A History,” includes rumination on cancer, lactation, and top surgery.

In a departure from trans narratives that describe a feeling of being born “in the wrong body,” Belc is frank about the losses and gains that come with transitioning and the impossibility of boxing his body or his experience into any tidy definition.

Describing a trans-masculine support group, he writes, “No one in the group talks about what one does if one cannot decide whether to keep [their breasts] or not. If it is normal to harbor both intense gratefulness and revulsion toward them. No one in my group has breastfed a child.”

And in the section titled “In the Court of Common Pleas,” Belc reprints the legal documents that scaffold a life — birth certificate, marriage license, adoption papers — while poking ironically at those “truths” in numbered footnotes.

These days, his literary dissections are upstaged by the churn of work — Belc is an outpatient education coordinator at Children’s Hospital of Philadelphia — and family life. On a recent Tuesday, the kids bounced through the family’s rowhouse.

Sean, 8, offered a shy wave before vanishing to the basement play area. Sully, 5, briefly enlisted 7-year-old Samson in a game that involved tossing dice and giving hugs.

The kids refer to Belc as “Dad” and call him by his first name. They know he’s trans, and they understand that he’s written a book about their family. “We talk about gender a lot,” Belc says. The book recounts how, when the older kids used to ask Sully if he was “a boy or a girl or both or neither,” Sully would answer, “I am a baby.

“In this family,” Belc writes, “there is always a chance to redefine how you see yourself.”