In the kindergarten Nativity play, he was Joseph and she was Mary.

Thirty-two years later, their conception story was just as unlikely.

Since the age of 14, Audrey had suffered severe endometriosis, as well as a rare uterine abnormality. She had endured two surgeries, taken birth control pills to control the bleeding and pain, and had long since given up on the possibility of childbearing.

"I was always told by doctors that I would most likely never get pregnant, and if I did, I probably couldn't carry to term," she says. At first, that news stymied her - "for a long time, I didn't date because I thought most guys would want children" - but by her 30s, she had made peace with a childless life.

John never yearned for kids. "I had more of a 'take it or leave it' attitude," he says. "And by my late 30s, when I was still single, I figured it wasn't going to happen for me."

Then Audrey bumped her head. She slipped on a patch of ice outside her Wallingford condo in February 2014 and ended up in an emergency room where her long-ago classmate was a paramedic.

Even though she and John had gone through school together - Our Lady of Peace in Milmont Park, then Ridley High School, landing in the same homeroom because their last names were alphabetical kin - they had divergent interests. Audrey worked on the yearbook committee; John immersed himself in the high school TV and radio station.

They were Facebook "friends" who hadn't actually seen each other in years. But after that ER visit, John messaged Audrey: "If you need anything, let me know."

"I thought, Oh, good, he's a paramedic. I can ask him questions." She quizzed him about her concussion symptoms - headaches and dizziness - and her concern about falling asleep alone.

Facebook messages segued to texting, then to a plan to meet at Iron Hill Brewery in Media. "I didn't know if we were just getting drinks and appetizers," Audrey says. "But he ordered dinner, and I thought, 'Oh, maybe this is a date.' We ended up talking for so long. I knew I was interested."

Audrey, a paralegal, was between jobs for a few months, which left her open for daytime dates - an art exhibit at Drexel University, a long weekend at the Shore for Memorial Day.

They never talked about children. They were only just starting to talk about plans - a Mexico vacation this year, a wedding sometime in the fuzzy future - when Audrey realized she had been feeling persistently ill.

"I was dizzy. Gagging. Nauseous. Then I almost fainted in the shower." She squeezed in a doctor visit on her lunch hour; she figured this was one more chapter in her saga of gynecological woes. Instead, the doctor tested her urine and returned with jarring news.

"I was nine weeks pregnant," Audrey says. "I was shocked. It was literally the last thing I ever expected. I'd never pictured myself as a mom."

And though John remained outwardly calm that day after work when she told him, a thousand panicked thoughts raced through his head: "How can we afford college in 18 years? Are we going to live here [in Drexel Hill]? What schools will the kid go to? I was scared of the unknown."

Audrey knew that a fetus was considered viable at 24 weeks; at first, her goal was to carry safely until that milestone. Roiled by nausea, she gulped Zofran every day and ate a bland diet of baked potatoes, plain chicken, and soft pretzels. Each ultrasound brought anxiety, then reprieve: The baby was still there, with its tiny, thrumming heart.

They scheduled a hospital tour and planned a C-section for mid-July. But over Memorial Day weekend, Audrey began feeling intense pelvic pain. At Lankenau Medical Center, she was admitted for monitoring. "I wasn't having contractions, and I wasn't dilated, but it was the most severe pain I've ever been in."

At 5 a.m., the baby's heart rate took a dive; suddenly, Audrey was initialing consent forms and being whisked to an operating room. "I kept hearing the surgeon say, 'We need to get this baby out.' The next thing I remember was them waking me up."

John, shaken and relieved, was in the hallway. Their 4-pound, 7-ounce daughter lay in an incubator in the NICU. Audrey marveled at her size - big for a preemie - and her reddish-orange hair. John took sober note of the machines tethered to her body: heart monitor, oxygen sensor, arterial line in her umbilical to measure blood pressure.

For six weeks, their days started with a 5 a.m. email from the NICU nurses, written as though it were from Grace: "Hi, Mommy and Daddy," it began, then detailed how many milliliters of formula she had taken, how many times she had pooped, how many ounces she'd added to her tiny frame.

John drew on his expertise - he had been a flight paramedic at Children's Hospital of Philadelphia - to coach Audrey in diaper-changing. Nurses showed them how to give the baby a bath. The last hurdle was the feeding tube; when that came out, Grace could go home.

Audrey dressed her for the occasion in an outfit she'd bought on a splurge from a fancy shop in Haddonfield - a pink-and-white onesie with a matching sweater and ruffled socks.

Now, Grace is right on schedule: She laughs at her stuffed monkeys and babbles consonant sounds. Sometimes, she sleeps through the night. It's her parents who struggle, at times, to absorb the startling lurch in their lives.

Audrey remembers watching friends with children and thinking: I could never do that. "I thought it looked so hard. Now we're doing it."

The reality of this baby is undeniable; Grace is more herself each day. "Her smile, the faces she makes, the baby talk," John says. "At the same time, it still feels like a dream."